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by BojanaL at 10-11-2012, 03:46 PM
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A guide for higher education in biotechnology including a list of popular universities/colleges in Europe. Best places to do Masters or PhD in various Life Science fields.
To become successful in biotechnology, you need to get a proper education first. Here’s the list of few European schools that are providing enough knowledge for any career in biotech you want.
University of Natural Resources & Applied Life Sciences in Vienna, Austria
It’s founded in 1872. Over 10 000 students are currently enrolled in studding programs at BOKU (“Universität für Bodenkultur” – German name for the university). It is research centre for renewable resources. If you are interested in agricultural engineering and water management, food and biotechnology, landscape architecture, natural resource management and ecological engineering, environmental engineering, food science and biotechnology, organic farming, phytomedicine… - beautiful Vienna is perfect place for you.
Karolinska Institute in Stockholm, Sweden
It’s one of the largest and most prestigious medical universities in Europe. One of the greatest achievements associated with this university is discovery that mature cells can be reprogrammed to become pluripotent, which is rewarded with a Nobel Prize in Physiology and Medicine in 2012. It’s founded in 1810 and has 2 campuses. For all people interested in Life science – Karolinska is excellent choice (among 20 best life science colleges in the world). You can choose some of the following departments: cell and molecular biology, environmental medicine, medical biochemistry and biophysics, medical epidemiology and biostatistics, microbiology, tumor and cell biology, neuroscience, physiology and pharmacology, molecular medicine and surgery, oncology-pathology, biosciences and nutrition, laboratory medicine, neurobiology…
ETH Zurich, Switzerland
ETH Zurich is founded in 1854. Main research areas are associated with mathematics, engineering and architecture beside natural and system-oriented sciences. It won 21 Nobel Prizes in the past and had several pretty famous students, such as Albert Einstein. Over 80 new patents are released each year and main focuses are energy supply, risk management, food security and human health. It’s one of the largest universities in Europe with over 17 000 students (from 80 different countries) and more than 400 teachers.
University of Cambridge, United Kingdom
Cambridge University is second oldest university in UK, founded in 1209. It holds a record in Nobel Prizes won – 65 so far. For the second consecutive years it’s ranked number 1, in the competition for the best university in the world, according to QS World University Rankings and U.S. News & World Report. It operates botanic garden and 8 art, scientific and cultural museums. List of famous people attending this college in the past is going all the way from Charles Darwin and Watson & Crick, to Stephen Hawking, Emma Thompson & Rachel Weisz. Graduation ceremony is unique: students wearing special academic dresses are taken by university officials to the vice-chancellor for the degree they are about to take. Praelector presents graduates and claims their knowledge using Latin language. Students are kneeling and proffering their hands to the vice-chancellor, who is clasping them and conferring degree they earned using Latin again. Nice way to conclude your college days.
University of Strasbourg, France
This is the largest University in France with over 43000 students and over 4000 teachers. It’s founded in 1631. In 1970 it was divided in three separate universities: Louis Pasteur University (focused on natural sciences, technology and medicine), Marc Bloch University (dealing with humanities subjects and the social sciences) and Robert Schuman University (operating with law, politics and international relations). As from January 2009, those three fused back together and today, University of Strasbourg is among the most respectful European colleges famous for high quality research and education provided.
Norwegian University of Life Sciences, Norway
UMB (Universitetet for miljø- og biovitenskap) is located in Ås, Norway. It’s famous for his beautiful surroundings (old trees, bushes, flowers…). Although established in 1859, it received university status in 2005. It’s divided in 8 departments (animal and aquacultural sciences, biotechnology and food science, ecology and natural resource management, landscape architecture and spatial planning, plant and environmental sciences…) and 6 centers (aquaculture protein center, animal production experimental centre, centre for plant research in controlled climate, centre for continuing education, the centre for integrative genetics and Norwegian centre for bioenergy research). It collaborates with lot of worldwide institutions and have exchange agreements with 93 universities/institutions worldwide (including 44 European and 8 North American), which allow people to come and experience Norwegian style of life and get a lot of valuable knowledge from environmental & food science and biotechnology.
Those were just few universities in Europe that could provide excellent education and research options. If you are coming from different country or even continent – whole experience will be even better because you’ll have a chance to meet a lot of people and exciting new cultures that are gathered on one place with same idea: to learn and develop in biotech field. Enjoy your student days where ever you are.
To become successful in biotechnology, you need to get a proper education first. Here’s the list of few European schools that are providing enough knowledge for any career in biotech you want.
University of Natural Resources & Applied Life Sciences in Vienna, Austria
It’s founded in 1872. Over 10 000 students are currently enrolled in studding programs at BOKU (“Universität für Bodenkultur” – German name for the university). It is research centre for renewable resources. If you are interested in agricultural engineering and water management, food and biotechnology, landscape architecture, natural resource management and ecological engineering, environmental engineering, food science and biotechnology, organic farming, phytomedicine… - beautiful Vienna is perfect place for you.
Karolinska Institute in Stockholm, Sweden
It’s one of the largest and most prestigious medical universities in Europe. One of the greatest achievements associated with this university is discovery that mature cells can be reprogrammed to become pluripotent, which is rewarded with a Nobel Prize in Physiology and Medicine in 2012. It’s founded in 1810 and has 2 campuses. For all people interested in Life science – Karolinska is excellent choice (among 20 best life science colleges in the world). You can choose some of the following departments: cell and molecular biology, environmental medicine, medical biochemistry and biophysics, medical epidemiology and biostatistics, microbiology, tumor and cell biology, neuroscience, physiology and pharmacology, molecular medicine and surgery, oncology-pathology, biosciences and nutrition, laboratory medicine, neurobiology…
ETH Zurich, Switzerland
ETH Zurich is founded in 1854. Main research areas are associated with mathematics, engineering and architecture beside natural and system-oriented sciences. It won 21 Nobel Prizes in the past and had several pretty famous students, such as Albert Einstein. Over 80 new patents are released each year and main focuses are energy supply, risk management, food security and human health. It’s one of the largest universities in Europe with over 17 000 students (from 80 different countries) and more than 400 teachers.
University of Cambridge, United Kingdom
Cambridge University is second oldest university in UK, founded in 1209. It holds a record in Nobel Prizes won – 65 so far. For the second consecutive years it’s ranked number 1, in the competition for the best university in the world, according to QS World University Rankings and U.S. News & World Report. It operates botanic garden and 8 art, scientific and cultural museums. List of famous people attending this college in the past is going all the way from Charles Darwin and Watson & Crick, to Stephen Hawking, Emma Thompson & Rachel Weisz. Graduation ceremony is unique: students wearing special academic dresses are taken by university officials to the vice-chancellor for the degree they are about to take. Praelector presents graduates and claims their knowledge using Latin language. Students are kneeling and proffering their hands to the vice-chancellor, who is clasping them and conferring degree they earned using Latin again. Nice way to conclude your college days.
University of Strasbourg, France
This is the largest University in France with over 43000 students and over 4000 teachers. It’s founded in 1631. In 1970 it was divided in three separate universities: Louis Pasteur University (focused on natural sciences, technology and medicine), Marc Bloch University (dealing with humanities subjects and the social sciences) and Robert Schuman University (operating with law, politics and international relations). As from January 2009, those three fused back together and today, University of Strasbourg is among the most respectful European colleges famous for high quality research and education provided.
Norwegian University of Life Sciences, Norway
UMB (Universitetet for miljø- og biovitenskap) is located in Ås, Norway. It’s famous for his beautiful surroundings (old trees, bushes, flowers…). Although established in 1859, it received university status in 2005. It’s divided in 8 departments (animal and aquacultural sciences, biotechnology and food science, ecology and natural resource management, landscape architecture and spatial planning, plant and environmental sciences…) and 6 centers (aquaculture protein center, animal production experimental centre, centre for plant research in controlled climate, centre for continuing education, the centre for integrative genetics and Norwegian centre for bioenergy research). It collaborates with lot of worldwide institutions and have exchange agreements with 93 universities/institutions worldwide (including 44 European and 8 North American), which allow people to come and experience Norwegian style of life and get a lot of valuable knowledge from environmental & food science and biotechnology.
Those were just few universities in Europe that could provide excellent education and research options. If you are coming from different country or even continent – whole experience will be even better because you’ll have a chance to meet a lot of people and exciting new cultures that are gathered on one place with same idea: to learn and develop in biotech field. Enjoy your student days where ever you are.
by Ishani7 at 10-11-2012, 02:02 AM
3 comments
The chromosomes represent genetic material of an organism and are the most stable organic compound that maintains constancy both in number and structure. However chromosomes undergo unusual changes called as aberrations which can be numerical or structural. In numerical aberrations, increase or decrease in number of chromosomes are seen. Types of numerical aberrations are:
• Euploidy- complete set of chromosomes present in multiples
• Aneuploidy- partial change in chromosomes
When there is an increase in number of chromosomes compared to the chromosomal number of an organ, then the condition is called as hyperaneuploidy. It is represented as 2n+1, 2n+2 etc. Aneuploidy is also classified as Monosomy, Trisomy and Nullisomy.
Monosomy is hypoaneuploidy where one of alleles of the homologous pair is lost. Monosomy is found rarely in diploids and is commonly found in polyploidy. Depending on the chromosome number, that many types of monosomies can develop. When two different chromosomes are lost, it's denoted as 2n-1-1, when 3 different chromosomes of a different homologous pair are lost, it is represented as 2n-1-1-1. It is called as tri Monosomy. Trisomy is a type of hyperaneuploidy where the number of individual chromosomes is more than the number of chromosomes in an organism. Edward syndrome is caused because of a trisomy. Nullisomy is the condition where both the alleles of a gene of the same pair of homologous chromosomes are lost. It is represented as 2n-2. Usually nullisomies hardly survive.
Euploidy exists in three conditions; monoploidy, haploidy and polyploidy. Monoploidy refers to the normal condition where one set of chromosome is present. Haploidy is the presence of half the number of chromosomes in a somatic cell. Haploidy can be induced by X rays, temperature shock, colchisin and delayed pollination. Experimental methods of developing haploidy involve distant hybridization, production of androgenic plants. Haploids usually produce sterile plants. Polyploidy is the condition where the number of chromosomes present in multiple copies. Types of polyploidy include autopolyploidy, allopolyploidy and segmental alloploidy.
Structural chromosomal aberrations can be intra chromosomal or inter chromosomal. Intra chromosomal structural aberrations include deletion, duplication and inversion. Inter chromosomal aberrations include translocations. Deletions can be terminal or inter special and can be caused naturally and also by chemical mutagens and radiation. These can be identified by size of the chain, change in the position of centromere and formation of loops in pachytene stage. Deletion of a portion of a dominant allele may result in expression of a recessive character. This is called as pseudodominance.
Duplication results in structural chromosomal aberrations. Duplications occur in a lower frequency than deletions. Bar eye mutation in Drosophila results in duplication in X chromosome. Inversion is an intra-chromosomal aberration where segment of chromosomes are inverted on reversed by 180 degrees. Inversions can be paracentric, where centromere is not involved or pericentric where the centromere is involved in the inverted segments of chromosome. Translocations involve two non-homologous chromosomes and position of part of the chromosome is changed leading to change in arrangement of chromosomes. Types of arrangements in translocation include alternate, adjacent I and adjacent 2. In simple translocation, a single nick occurs and the terminal position of the chromosome gets translocated on another non-homologous chromosome. In shifted translocations, two nicks are created and interstitial chromosome segment gets translocated onto another non-homologous chromosome. In reciprocal translocation, two nicks occur on both non-homologous chromosomes and separated segments get interchanged. The translocated chromosomes show change in the size of the chromosome and in position of the centromere. During pairing of homologous chromosomes, the translocate part forms a loop. Translocation brings about new linkage groups or new variation can be linked with normal genes. Translocation in human beings can lead to leukemia.
• Euploidy- complete set of chromosomes present in multiples
• Aneuploidy- partial change in chromosomes
When there is an increase in number of chromosomes compared to the chromosomal number of an organ, then the condition is called as hyperaneuploidy. It is represented as 2n+1, 2n+2 etc. Aneuploidy is also classified as Monosomy, Trisomy and Nullisomy.
Monosomy is hypoaneuploidy where one of alleles of the homologous pair is lost. Monosomy is found rarely in diploids and is commonly found in polyploidy. Depending on the chromosome number, that many types of monosomies can develop. When two different chromosomes are lost, it's denoted as 2n-1-1, when 3 different chromosomes of a different homologous pair are lost, it is represented as 2n-1-1-1. It is called as tri Monosomy. Trisomy is a type of hyperaneuploidy where the number of individual chromosomes is more than the number of chromosomes in an organism. Edward syndrome is caused because of a trisomy. Nullisomy is the condition where both the alleles of a gene of the same pair of homologous chromosomes are lost. It is represented as 2n-2. Usually nullisomies hardly survive.
Euploidy exists in three conditions; monoploidy, haploidy and polyploidy. Monoploidy refers to the normal condition where one set of chromosome is present. Haploidy is the presence of half the number of chromosomes in a somatic cell. Haploidy can be induced by X rays, temperature shock, colchisin and delayed pollination. Experimental methods of developing haploidy involve distant hybridization, production of androgenic plants. Haploids usually produce sterile plants. Polyploidy is the condition where the number of chromosomes present in multiple copies. Types of polyploidy include autopolyploidy, allopolyploidy and segmental alloploidy.
Structural chromosomal aberrations can be intra chromosomal or inter chromosomal. Intra chromosomal structural aberrations include deletion, duplication and inversion. Inter chromosomal aberrations include translocations. Deletions can be terminal or inter special and can be caused naturally and also by chemical mutagens and radiation. These can be identified by size of the chain, change in the position of centromere and formation of loops in pachytene stage. Deletion of a portion of a dominant allele may result in expression of a recessive character. This is called as pseudodominance.
Duplication results in structural chromosomal aberrations. Duplications occur in a lower frequency than deletions. Bar eye mutation in Drosophila results in duplication in X chromosome. Inversion is an intra-chromosomal aberration where segment of chromosomes are inverted on reversed by 180 degrees. Inversions can be paracentric, where centromere is not involved or pericentric where the centromere is involved in the inverted segments of chromosome. Translocations involve two non-homologous chromosomes and position of part of the chromosome is changed leading to change in arrangement of chromosomes. Types of arrangements in translocation include alternate, adjacent I and adjacent 2. In simple translocation, a single nick occurs and the terminal position of the chromosome gets translocated on another non-homologous chromosome. In shifted translocations, two nicks are created and interstitial chromosome segment gets translocated onto another non-homologous chromosome. In reciprocal translocation, two nicks occur on both non-homologous chromosomes and separated segments get interchanged. The translocated chromosomes show change in the size of the chromosome and in position of the centromere. During pairing of homologous chromosomes, the translocate part forms a loop. Translocation brings about new linkage groups or new variation can be linked with normal genes. Translocation in human beings can lead to leukemia.
by Ishani7 at 10-11-2012, 12:59 AM
0 comments
In 1961, Francis Jacob and Jacques Monad described Operon model for genetic control of lactose metabolism in E. coli. Operon refers to a group of genes that functions together to achieve a common task. Many bacterial genes function as operons. Vir operon in Ti plasmids is another example for an operon. Some operons are negatively induced while some are positively induced.
Lactose is one of the major carbohydrates and found in milk, known as milk sugar. It is a disaccharide consisting of Glucose and Galactose. Lactose does not easily diffuse across the E. coli cell membrane and must be actively transported into the cell by the enzyme permease. To utilize lactose as an energy source, E. coli must first break it into Glucose and Galactose, a reaction catalyzed by the enzyme β-galactosidase. This enzyme can also convert lactose into allolactose, a compound that plays an important role in regulating lactose metabolism. A third enzyme, thiogalactoside transacetylase, also is produced by lac operon, but its function in lactose metabolism is not yet known.
The lac operon is an example of a negative inducible operon. The enzymes β-galactosidase,permease and transacetylase are encoded by the structural genes in lac operon in E. coli. β-galactosidase is encoded by Lac Z gene, permease by Lac Y gene and transacetylase by Lac A gene. When lactose and glucose is absent in the medium, the rate of synthesis of all three enzymes simultaneously increases about a thousand within two or three minutes which is stimulated by a specific molecule, called as an inducer.
Although lactose appear to be the inducer here, allolactose is actually responsible for the induction. Lac Z gene, Lac Y gene and Lac A gene have a common promoter and are transcribed together. Upstream of the promoter is the regulator gene, Lac I, which has its own promoter. Lac I gene encodes a repressor protein. Each repressor protein consists of four identical polypeptides and has two binding sites; one site for binding with allolactose and the other for binding with DNA. In the absence of lactose, the repressor binds to the Lac operator site/Lac O and prevents the transcription of the lac genes by blocking binding of RNA polymerase.
When lactose is present, some of the lactose is converted into allolactose, which binds to the repressor and cause the repressor to be released from the DNA. Then the repressor is inactivated in the presence of lactose and the binding of RNA polymerase is no longer blocked. The transcription of Lac Z, Lac Y and Lac A takes place and the Lac enzymes are produced.
Repression never completely shuts down transcription of Lac operon. Even with the active repressor bound to the operator, there is low level of transcription and a few molecules of β-galactosidase, permease and transacetylase are synthesized.
When lactose appears in the medium; the permease present, transport a small amount of lactose into cell. There, the few molecules of β-galactosidase that are present, convert some of the lactose into allolactose. The allolactose then attaches to the repressor and alters its shape so that the repressor no longer binds to the operator. When the operator site is clear, RNA polymerase can bind and transcribe the structural genes of the operon.
Several compounds related to allolactose also can bind to the lac repressor and induce transcription of the Lac operon. One such inducer is isopropylthiogalactoside (IPTG). Although IPTG inactivated the repressor and allows the transcription of Lac Z, Lac Y and Lac A; this inducer is not metabolized by β-galactosidase.
The regulation of Lac operon is used in screening of competent cells Blue white selection. There, the mutants lack the ability to produce β-galactosidase whereas the non- transformed cells can produce β-galactosidase. The produced β-galactosidase will form a complex with X gal in the medium which appear in blue colour. IPTG acts as the inducer for the activation of lac genes.
Lactose is one of the major carbohydrates and found in milk, known as milk sugar. It is a disaccharide consisting of Glucose and Galactose. Lactose does not easily diffuse across the E. coli cell membrane and must be actively transported into the cell by the enzyme permease. To utilize lactose as an energy source, E. coli must first break it into Glucose and Galactose, a reaction catalyzed by the enzyme β-galactosidase. This enzyme can also convert lactose into allolactose, a compound that plays an important role in regulating lactose metabolism. A third enzyme, thiogalactoside transacetylase, also is produced by lac operon, but its function in lactose metabolism is not yet known.
The lac operon is an example of a negative inducible operon. The enzymes β-galactosidase,permease and transacetylase are encoded by the structural genes in lac operon in E. coli. β-galactosidase is encoded by Lac Z gene, permease by Lac Y gene and transacetylase by Lac A gene. When lactose and glucose is absent in the medium, the rate of synthesis of all three enzymes simultaneously increases about a thousand within two or three minutes which is stimulated by a specific molecule, called as an inducer.
Although lactose appear to be the inducer here, allolactose is actually responsible for the induction. Lac Z gene, Lac Y gene and Lac A gene have a common promoter and are transcribed together. Upstream of the promoter is the regulator gene, Lac I, which has its own promoter. Lac I gene encodes a repressor protein. Each repressor protein consists of four identical polypeptides and has two binding sites; one site for binding with allolactose and the other for binding with DNA. In the absence of lactose, the repressor binds to the Lac operator site/Lac O and prevents the transcription of the lac genes by blocking binding of RNA polymerase.
When lactose is present, some of the lactose is converted into allolactose, which binds to the repressor and cause the repressor to be released from the DNA. Then the repressor is inactivated in the presence of lactose and the binding of RNA polymerase is no longer blocked. The transcription of Lac Z, Lac Y and Lac A takes place and the Lac enzymes are produced.
Repression never completely shuts down transcription of Lac operon. Even with the active repressor bound to the operator, there is low level of transcription and a few molecules of β-galactosidase, permease and transacetylase are synthesized.
When lactose appears in the medium; the permease present, transport a small amount of lactose into cell. There, the few molecules of β-galactosidase that are present, convert some of the lactose into allolactose. The allolactose then attaches to the repressor and alters its shape so that the repressor no longer binds to the operator. When the operator site is clear, RNA polymerase can bind and transcribe the structural genes of the operon.
Several compounds related to allolactose also can bind to the lac repressor and induce transcription of the Lac operon. One such inducer is isopropylthiogalactoside (IPTG). Although IPTG inactivated the repressor and allows the transcription of Lac Z, Lac Y and Lac A; this inducer is not metabolized by β-galactosidase.
The regulation of Lac operon is used in screening of competent cells Blue white selection. There, the mutants lack the ability to produce β-galactosidase whereas the non- transformed cells can produce β-galactosidase. The produced β-galactosidase will form a complex with X gal in the medium which appear in blue colour. IPTG acts as the inducer for the activation of lac genes.
by Ishani7 at 10-10-2012, 10:30 PM
0 comments
Food packaging is an important step in food manufacturing operations. Food packaging ensures the shelf life of the food item protecting it from external barriers such as insect pests, microbes and also from light, moisture, oxygen etc. Some products are stored in transparent glass containers. Such products should not be sensitive to light. Products which can be degraded by light should be stored in brown glass or with packaging material having high light barrier properties. Food items with high fat contents are subjected to oxidation in the presence of oxygen. Another concern of the modern society is that the packaging should be ecofriendly and should be readily degraded. So depending on the product marketer have to select the packaging material to protect the product. Food packaging can be referred as food protection systems.
Most packaging materials traditionally used are polymers and are not easily degradable. Barrier properties of the packaging material are also important to determine the shelf life of the product. For an instance, for a fatty food Oxygen barrier properties are important. The empty space over the product in packaged food is called as head space. A proper packaging material protects preserves, promotes and informs the food item.
Polymers used for packaging include polyethylene, polypropylene, Polyvinyl chloride, Polyvinilydine chloride and Polyethylene terephthalate etc. PET and HDPE are recyclable. For respiring food items, packaging material with high barrier properties are not suitable as it leads to rotting due to moisture accumulation. Triple laminates are used to package dried products to prevent it from moisture and to prevent escape of volatile aroma compounds. Food items with pigments/dyes important for the quality of the product; are packed in light protective containers.
Apart from these traditional methods of packaging, new trends such as active packaging, intelligent packaging has scope. In active packaging, subsidiary constituents have been deliberately included in or either the packaging material or the package headspace to enhance the performance of packaging material. In this, active compounds are filled into sachets or pads which are placed inside packages or active compounds can be directly incorporated into the packaging material. These active compounds include Oxygen scavengers/absorbers that include powdered iron, ascorbic acid. Iron powder reduces the Oxygen concentration in the headspace to less than 0.01%. Water is essential for Oxygen absorbers to function. Nonmetallic absorbers include ascorbic acid, ascorbate salt and catechol. Enzymatic oxygen scavengers include glucose oxidase, ethanol oxidase incorporated into sachets, adhesive labels or immobilized onto package surface. Apart from these vacuum packaging and Nitrogen flushing is used to remove Oxygen from the package.
As Oxygen, Carbon dioxide also can be problematic to the packaged food item as it can lead to an anaerobic environment with an acidic pH. Carbon dioxide absorbers are used to remove this. Sometimes Carbon dioxide emitters are inserted into food packaging to create anaerobic conditions. Generally used Carbon dioxide emitters are Ascorbic acid with Ferrous carbonate, Ascorbic acid with Sodium bicarbonate. These chemicals absorb Oxygen and generate equivalent amount of Carbon dioxide. CO2 emitters avoid package collapse and development of a partial vacuum. Ethylene absorbers such as Potassium permanganate oxidize ethylene to Carbon dioxide and water.
Ethanol emitters show antimicrobial effects even at lower concentrations. The substance is filled into a paper copolymer sachet. Some sachets contain traces of vanilla and other aroma compounds to mask the alcohol odour. The sachet contents absorb moisture from the food and releases ethanol vapour. Water activity of the food is an important factor in this type of packaging. This is widely used in Japan to extend the shelf life of high moisture bakery products upto 20 times the normal. Moisture absorbers are also heavily used which include Polyacrylate salts, activated clay, silica gel. Moisture accumulation can result from temperature fluctuations, drip of tissue fluid from flesh and during respiration of horticultural products. This can lead to growth of molds and bacteria.
Intelligent packaging is a great advantage of food biotechnology. In this, different sensors are used in food package which indicates about the quality of the food to the consumer. These sensors are coupled with biochemical reaction taking place inside the food when deterioration of the quality of food such as lipid oxidation, rotting of fruits etc. Gas indicators are one type of intelligent packaging. Thermochromic inks which are sensitive to temperature and microwave doness indicators (MDI) which emit audible signals when the food is ready to serve are some advance applications.
Most packaging materials traditionally used are polymers and are not easily degradable. Barrier properties of the packaging material are also important to determine the shelf life of the product. For an instance, for a fatty food Oxygen barrier properties are important. The empty space over the product in packaged food is called as head space. A proper packaging material protects preserves, promotes and informs the food item.
Polymers used for packaging include polyethylene, polypropylene, Polyvinyl chloride, Polyvinilydine chloride and Polyethylene terephthalate etc. PET and HDPE are recyclable. For respiring food items, packaging material with high barrier properties are not suitable as it leads to rotting due to moisture accumulation. Triple laminates are used to package dried products to prevent it from moisture and to prevent escape of volatile aroma compounds. Food items with pigments/dyes important for the quality of the product; are packed in light protective containers.
Apart from these traditional methods of packaging, new trends such as active packaging, intelligent packaging has scope. In active packaging, subsidiary constituents have been deliberately included in or either the packaging material or the package headspace to enhance the performance of packaging material. In this, active compounds are filled into sachets or pads which are placed inside packages or active compounds can be directly incorporated into the packaging material. These active compounds include Oxygen scavengers/absorbers that include powdered iron, ascorbic acid. Iron powder reduces the Oxygen concentration in the headspace to less than 0.01%. Water is essential for Oxygen absorbers to function. Nonmetallic absorbers include ascorbic acid, ascorbate salt and catechol. Enzymatic oxygen scavengers include glucose oxidase, ethanol oxidase incorporated into sachets, adhesive labels or immobilized onto package surface. Apart from these vacuum packaging and Nitrogen flushing is used to remove Oxygen from the package.
As Oxygen, Carbon dioxide also can be problematic to the packaged food item as it can lead to an anaerobic environment with an acidic pH. Carbon dioxide absorbers are used to remove this. Sometimes Carbon dioxide emitters are inserted into food packaging to create anaerobic conditions. Generally used Carbon dioxide emitters are Ascorbic acid with Ferrous carbonate, Ascorbic acid with Sodium bicarbonate. These chemicals absorb Oxygen and generate equivalent amount of Carbon dioxide. CO2 emitters avoid package collapse and development of a partial vacuum. Ethylene absorbers such as Potassium permanganate oxidize ethylene to Carbon dioxide and water.
Ethanol emitters show antimicrobial effects even at lower concentrations. The substance is filled into a paper copolymer sachet. Some sachets contain traces of vanilla and other aroma compounds to mask the alcohol odour. The sachet contents absorb moisture from the food and releases ethanol vapour. Water activity of the food is an important factor in this type of packaging. This is widely used in Japan to extend the shelf life of high moisture bakery products upto 20 times the normal. Moisture absorbers are also heavily used which include Polyacrylate salts, activated clay, silica gel. Moisture accumulation can result from temperature fluctuations, drip of tissue fluid from flesh and during respiration of horticultural products. This can lead to growth of molds and bacteria.
Intelligent packaging is a great advantage of food biotechnology. In this, different sensors are used in food package which indicates about the quality of the food to the consumer. These sensors are coupled with biochemical reaction taking place inside the food when deterioration of the quality of food such as lipid oxidation, rotting of fruits etc. Gas indicators are one type of intelligent packaging. Thermochromic inks which are sensitive to temperature and microwave doness indicators (MDI) which emit audible signals when the food is ready to serve are some advance applications.
by Ishani7 at 10-10-2012, 09:20 PM
0 comments
Chocolates are the wonder product comes out from cocoa. Cocoa fruits are yellow pods with a violet colour kernel. Many varieties are found in different countries such as Criollo, Trinitaro etc. Size, kernel colour, sensitivity to disease may vary depending on the variety.
After collecting the harvest, the fruits are left for few days for the attached seeds to detach from the husk. Shell and silver skin is removed when making chocolates with cocoa. Mucilage consists of nutrients, which are degraded by microbes during fermentation which results in change in flavour and aroma.
Cocoa seeds do not germinate during fermentation as microbial activity releases heat and the internal temperature rises. Inhibiting germination is one purpose of leaving the seeds for fermentation. Mucilage acts as a barrier to moisture removal. After fermentation, it can be easily removed and dried. Many biochemical reactions occur during fermentation.
The scientists have investigated cocoa fermentation and realized that the microflora were responsible for the maceration of pulp of the mucilage and killing the seeds. The seeds in a pod are sterile. When the seeds are extracted from the pods after harvesting by manual operations, they get exposed into the atmosphere where the microbes come in contact with the seeds. Fungi, Yeast and bacteria are generally involved in this fermentation process. Fungi like Aspergillus, Mucor, Penicillium, Rhizopus ; Yeasts like Saccharomyces, Pachia, Kloeckera, Candida and bacteria like lactic acid bacteria, acetic acid bacteria participate in fermentation. In first few hours of fermentation, yeast multiplication takes place. The pH of the mucilage will be around 3.6. In later stages, the environment inside the pod becomes anaerobic. Yeasts utilize the sugars in mucilage and produce Carbon dioxide. Initial temperature which was about 25 0 C rises to about 32-36 0C. Yeasts consume citric acid available in the mucilage and results in pH increase up to 4. Yeasts release pecteolytic enzymes which hydrolyzes the pectin.
In these conditions; pH 4 and temperature 320 C and anaerobic; lactic acid bacteria starts to grow. As the amount of sugars left is low, this occurs at a short period of time. These bacteria produce lactic acid. Acetic acid bacteria develop when alcohol is released into the medium as an end product by other microbes. Acetic acid bacteria convert lactic acid to acetic acid to convert energy. Small amount of acetic acid will be evaporated and the remaining penetrates into the kernel. This increases the cell wall permeability and results in further increase in pH and consequently allows biochemical reactions introducing precursors of aroma and flavour compounds. At increased pH levels, many bacteria tend to grow. In the final stages, the matrix will be rich with bacteria which break down and produce amide and some ammonical compounds. By this time, mucilage is degraded.
In the cotyledon, protein breakdown, formation of complex compounds with polyphenols, sugar hydrolysis, diffusion of organic acids and increase in permeability results. Sugar breakdown products are essential precursors of chocolate aroma. Some compounds like aldehydes, pyrazines produced are directly involved in aroma development. Caffeine and theobromine which are alkaloids diffuse from kernel cells into the outside matrix decreasing the bitterness. Polyphenolic compounds and alkaloids in pigmented cells are increased by 8-18% during fermentation. These involve flavonols, anthocyanidines, hydrocinamic derivatives and coumarin. Organic acids produced include Citric acid, Acetic acid, Lactic acid, Oxalic acid and Mallic acid. After fermentation drying rate can be increased and eventually washing away the mucilage of fermented cocoa beans.
After fermentation, beans with mucilage and placenta have to be separated from the husk pieces after the mechanical breakage. This operation is often more difficult than opening the pods. Cleaned fermented cocoa beans are roasted at 160 0C for three hours which allows enhancement of aroma and flavour followed by conching. During conching, the bitterness further reduces and also reduces the level of acetic acid. Roasting step is not sufficient to remove acetic acid.
When making chocolates, as the chocolate powder particles are very fine, the surface area is enormously large and the added fat is covered around the particle. The fat layer around the fine particles adsorb flavour and aroma compounds. Therefore, flavour characteristics are improved in the final product.
After collecting the harvest, the fruits are left for few days for the attached seeds to detach from the husk. Shell and silver skin is removed when making chocolates with cocoa. Mucilage consists of nutrients, which are degraded by microbes during fermentation which results in change in flavour and aroma.
Cocoa seeds do not germinate during fermentation as microbial activity releases heat and the internal temperature rises. Inhibiting germination is one purpose of leaving the seeds for fermentation. Mucilage acts as a barrier to moisture removal. After fermentation, it can be easily removed and dried. Many biochemical reactions occur during fermentation.
The scientists have investigated cocoa fermentation and realized that the microflora were responsible for the maceration of pulp of the mucilage and killing the seeds. The seeds in a pod are sterile. When the seeds are extracted from the pods after harvesting by manual operations, they get exposed into the atmosphere where the microbes come in contact with the seeds. Fungi, Yeast and bacteria are generally involved in this fermentation process. Fungi like Aspergillus, Mucor, Penicillium, Rhizopus ; Yeasts like Saccharomyces, Pachia, Kloeckera, Candida and bacteria like lactic acid bacteria, acetic acid bacteria participate in fermentation. In first few hours of fermentation, yeast multiplication takes place. The pH of the mucilage will be around 3.6. In later stages, the environment inside the pod becomes anaerobic. Yeasts utilize the sugars in mucilage and produce Carbon dioxide. Initial temperature which was about 25 0 C rises to about 32-36 0C. Yeasts consume citric acid available in the mucilage and results in pH increase up to 4. Yeasts release pecteolytic enzymes which hydrolyzes the pectin.
In these conditions; pH 4 and temperature 320 C and anaerobic; lactic acid bacteria starts to grow. As the amount of sugars left is low, this occurs at a short period of time. These bacteria produce lactic acid. Acetic acid bacteria develop when alcohol is released into the medium as an end product by other microbes. Acetic acid bacteria convert lactic acid to acetic acid to convert energy. Small amount of acetic acid will be evaporated and the remaining penetrates into the kernel. This increases the cell wall permeability and results in further increase in pH and consequently allows biochemical reactions introducing precursors of aroma and flavour compounds. At increased pH levels, many bacteria tend to grow. In the final stages, the matrix will be rich with bacteria which break down and produce amide and some ammonical compounds. By this time, mucilage is degraded.
In the cotyledon, protein breakdown, formation of complex compounds with polyphenols, sugar hydrolysis, diffusion of organic acids and increase in permeability results. Sugar breakdown products are essential precursors of chocolate aroma. Some compounds like aldehydes, pyrazines produced are directly involved in aroma development. Caffeine and theobromine which are alkaloids diffuse from kernel cells into the outside matrix decreasing the bitterness. Polyphenolic compounds and alkaloids in pigmented cells are increased by 8-18% during fermentation. These involve flavonols, anthocyanidines, hydrocinamic derivatives and coumarin. Organic acids produced include Citric acid, Acetic acid, Lactic acid, Oxalic acid and Mallic acid. After fermentation drying rate can be increased and eventually washing away the mucilage of fermented cocoa beans.
After fermentation, beans with mucilage and placenta have to be separated from the husk pieces after the mechanical breakage. This operation is often more difficult than opening the pods. Cleaned fermented cocoa beans are roasted at 160 0C for three hours which allows enhancement of aroma and flavour followed by conching. During conching, the bitterness further reduces and also reduces the level of acetic acid. Roasting step is not sufficient to remove acetic acid.
When making chocolates, as the chocolate powder particles are very fine, the surface area is enormously large and the added fat is covered around the particle. The fat layer around the fine particles adsorb flavour and aroma compounds. Therefore, flavour characteristics are improved in the final product.
by Ishani7 at 10-10-2012, 08:13 PM
0 comments
According to the central dogma of molecular biology, gene expression is regulated through copying the DNA sequence into mRNA and production of encoded proteins. In this synthesizing mRNA complementary to DNA is called transcription. Transcription is generally different from prokaryotes to eukaryotes. Transcription in eukaryotes consists of initiation, elongation and termination.
Eukaryotic cells possess three different RNA Polymerases which transcribe the genes for three types of RNA’s: RNA polymerase I exclusively located in nucleolus catalyzes the synthesis of ribosomal RNA, RNA polymerase II found in nucleoplasm catalyzes the synthesis of messenger RNA and RNA polymerase III in nucleoplasm responsible for synthesis of transfer RNA. Nature of promoter recognition and initiation in transcription is different in eukaryotes than in prokaryotes.
Transcription requires the sequences on DNA that are accessible to RNA polymerase and other proteins. However, in eukaryotic cells, DNA is complexed with histone proteins in highly compressed chromatin. Therefore before transcription the chromatin structure is modified so that the DNA will come to a more open configuration and is more accessible to the transcription machinery. Enzymes involved in this modification are acetyl transferases; which adds acetyl groups to amino acids at the ends of histone proteins leading to destabilization of the nucleosome structure and makes the DNA more accessible. Chromatin remodeling proteins bind to the chromatin and displace nucleosome from promoters and other regions important for transcription.
Promoter sequences are adjacent to the genes that it regulates. Enhancer sequences are not always adjacent to the regulated genes. Promoters and enhancers are important sequences for the initiation of transcription. In eukaryotic cells, promoter recognition is carried out by accessory proteins that bind to the sequence and then recruit a specific RNA polymerase to the promoter. These comprises of general transcription factors and transcription activator proteins.
A promoter for a gene transcribed by RNA polymerase II which is the major enzyme involved typically includes one or more consensus sequences. The most common is the TATA box which has the consensus sequence TATAAA. Apart from these TFII B recognition element serves as a consensus sequence. These specific sequences in the core promoter are recognized by transcription factors that bind to them and serve as a platform for the assembly of the basal transcription apparatus. The basal transcription apparatus binds to the DNA at the start site and require for initiation. This consists of RNA polymerase, a series of general transcription factors and a complex of proteins called as mediator. General transcription factors include TFII A, TFII B, TFII D etc. These are involved in stabilizing interactions, selection of start site, active site for RNA polymerase and helicase activity to unwind DNA. Regulatory promoters are sequences located immediately upstream of the core promoter. Enhancers are involved in increasing the rate of transcription. Sometimes enhancers are act to repress transcription and these are known as silencers.
After several nucleotides have been linked together, RNA polymerase leaves the promoter and disassociates from transcription factors moving downstream. During elongation, the RNA polymerase maintains a transcription bubble in which about eight nucleotides of RNA remain base paired with DNA template.
In the course of elongation, the two strands of DNA are unwound and the Ribonucleotides that are complementary to the template strand are added to the growing 3’ end of the RNA molecule. As it funnels through the polymerase, the DNA-RNA hybrid hits the wall of amino acids, bend at almost right angle. At this bent position new nucleotides are added. The newly synthesized RNA is separated from DNA and runs through another groove before exiting from the polymerase.
Termination mechanism differs depending on the type of RNA polymerase. RNA polymerase I requires a termination factor which binds to the DNA sequence downstream of the termination site. RNA polymerase III terminates transcription after transcribing a terminator sequence that produces a string of Uracil nucleotides in the RNA molecule. Unlike the rho factor independent terminators in bacterial cells, RNA polymerase III does not require hairpin structure to proceed the string of Uracils. Research findings suggest that termination is coupled to a cleavage which is carried out by a cleavage complex that is probably associated with RNA polymerase.
At the end of transcription, a messenger RNA molecule complementary to the DNA is formed and this m RNA serve as the template for protein synthesis in translation.
Eukaryotic cells possess three different RNA Polymerases which transcribe the genes for three types of RNA’s: RNA polymerase I exclusively located in nucleolus catalyzes the synthesis of ribosomal RNA, RNA polymerase II found in nucleoplasm catalyzes the synthesis of messenger RNA and RNA polymerase III in nucleoplasm responsible for synthesis of transfer RNA. Nature of promoter recognition and initiation in transcription is different in eukaryotes than in prokaryotes.
Transcription requires the sequences on DNA that are accessible to RNA polymerase and other proteins. However, in eukaryotic cells, DNA is complexed with histone proteins in highly compressed chromatin. Therefore before transcription the chromatin structure is modified so that the DNA will come to a more open configuration and is more accessible to the transcription machinery. Enzymes involved in this modification are acetyl transferases; which adds acetyl groups to amino acids at the ends of histone proteins leading to destabilization of the nucleosome structure and makes the DNA more accessible. Chromatin remodeling proteins bind to the chromatin and displace nucleosome from promoters and other regions important for transcription.
Promoter sequences are adjacent to the genes that it regulates. Enhancer sequences are not always adjacent to the regulated genes. Promoters and enhancers are important sequences for the initiation of transcription. In eukaryotic cells, promoter recognition is carried out by accessory proteins that bind to the sequence and then recruit a specific RNA polymerase to the promoter. These comprises of general transcription factors and transcription activator proteins.
A promoter for a gene transcribed by RNA polymerase II which is the major enzyme involved typically includes one or more consensus sequences. The most common is the TATA box which has the consensus sequence TATAAA. Apart from these TFII B recognition element serves as a consensus sequence. These specific sequences in the core promoter are recognized by transcription factors that bind to them and serve as a platform for the assembly of the basal transcription apparatus. The basal transcription apparatus binds to the DNA at the start site and require for initiation. This consists of RNA polymerase, a series of general transcription factors and a complex of proteins called as mediator. General transcription factors include TFII A, TFII B, TFII D etc. These are involved in stabilizing interactions, selection of start site, active site for RNA polymerase and helicase activity to unwind DNA. Regulatory promoters are sequences located immediately upstream of the core promoter. Enhancers are involved in increasing the rate of transcription. Sometimes enhancers are act to repress transcription and these are known as silencers.
After several nucleotides have been linked together, RNA polymerase leaves the promoter and disassociates from transcription factors moving downstream. During elongation, the RNA polymerase maintains a transcription bubble in which about eight nucleotides of RNA remain base paired with DNA template.
In the course of elongation, the two strands of DNA are unwound and the Ribonucleotides that are complementary to the template strand are added to the growing 3’ end of the RNA molecule. As it funnels through the polymerase, the DNA-RNA hybrid hits the wall of amino acids, bend at almost right angle. At this bent position new nucleotides are added. The newly synthesized RNA is separated from DNA and runs through another groove before exiting from the polymerase.
Termination mechanism differs depending on the type of RNA polymerase. RNA polymerase I requires a termination factor which binds to the DNA sequence downstream of the termination site. RNA polymerase III terminates transcription after transcribing a terminator sequence that produces a string of Uracil nucleotides in the RNA molecule. Unlike the rho factor independent terminators in bacterial cells, RNA polymerase III does not require hairpin structure to proceed the string of Uracils. Research findings suggest that termination is coupled to a cleavage which is carried out by a cleavage complex that is probably associated with RNA polymerase.
At the end of transcription, a messenger RNA molecule complementary to the DNA is formed and this m RNA serve as the template for protein synthesis in translation.
by Kamat2010 at 10-10-2012, 08:11 PM
2 comments
In the last decade, there has been vast development in the field of science and biomedicine. The whole sequencing of the human genome is certainly a milestone in the development and progress of science. This has helped in the rapid development in the field of medicine by providing knowledge about gene therapy, individual-based treatment for various diseases, different modes of treatment for genetic diseases, etc. Proteome can be defined as the set of various proteins expressed by a particular genome. The study of the different proteins, their dynamics and their interplay and interactions constitute the study of proteomics.
Although, both Proteomics and Protein chemistry involve the identification of various proteins expressed within the body, they are totally unrelated to each other. The protein chemistry is a part of the structural biology, dealing with physical biochemistry of the various proteins from a mechanistic point of view and relates mainly to the structure and function modelling studies and the effect of one on the other. Proteomics, on the other hand, involves systems biology, dealing with multiprotein systems and characterizing the behaviour of the whole system.
Measurement of gene expression is possible using various techniques; however, study of proteomics plays an important role considering the instability of the mRNAs preventing the formation of proteins as well as the regulatory functions of the different proteins in the biological and molecular mechanisms within the body. The gene expression can be measured by the use of cDNA as well as microarray system. Analysis of proteome is a complex task owing to the presence of posttranslational modification in proteins and also the fact that protein recognition is not based on sequence unlike oligonucleotides. Hence, special tools have been developed for proteomics such as
i)databases of protein, EST and genome sequence Mass spectrometry (MS),
ii)Mass Spectrometry (MS)
iii)collection of software that is capable of comparing the MS data with the protein sequence database, and
iv)protein separation technology
Analytical proteomics has become an emerging field in science. The identification of different proteins within the cell and their characterization is gaining importance even in medical field. The analysis of the whole protein is somewhat difficult. Hence, the tools for proteomics utilize different approaches for proper protein analysis. The protein is firstly converted to peptides and the sequence of the peptides is analysed. The sequence of the peptides is then matched with the sequence in the database to identify the proteins. The main problem in proteomics is the presence of a protein mixture in the biological sample. The protein analysis with the use of mixture is difficult; hence, the separation of the proteins is essential. The separation techniques involve the use of SDS-PAGE, which may be one-dimensional (1D) or two-dimensional (2D), High Performance Liquid Chromatography (HPLC). Proteins have also been analysed by digesting them and then carrying out separation using capillary electrophoresis or Isoelectric focusing (IEF). However, the protein separation by 2D SDS-PAGE followed by digestion into peptide fragments has emerged to be the better approach in analytical proteomics, due to numerous advantages offered by 2D SDS-PAGE. The proteins are digested using various proteases, which cleave at specific amino acids, thereby helping in the analysis with MS. Two types of instruments have been used for proteomics study: the MALDI-TOF and the ESI-tandem MS. Although, both the instruments work on completely different principles, they provide complementary information, hence both serve definite unique purpose. Peptide mass fingerprinting is a protein identification method used in high throughput proteomic study. In this method, the proteins are digested using trypsin and mass is analysed using MALDI-TOF. However, the difficulty in differentiation of homologous proteins and the similar proteins from different species limit the use of the method.
The main four applications of proteomics are:- Mining, protein expression profiling, protein network mapping and mapping of protein modifications. Mining refers to the identification of the proteins in a given sample i.e. the composition of the proteome is identified from the gene expression data from microarrays. Protein expression profiling is the identification of protein composition specific for a particular state of an organism or as a function to the effect of a drug or any other stimulus. Protein network mapping refers to the study of the interactions of various proteins in the functional network within the body and gives detailed information about the proteins in any signal transduction pathway. Mapping of protein modifications involves the study and identification of the nature and specificity of the posttranslational modification in a given protein. The development of protein arrays is under progress and if found successful, will create a great impact in the field of proteomics.
Although, both Proteomics and Protein chemistry involve the identification of various proteins expressed within the body, they are totally unrelated to each other. The protein chemistry is a part of the structural biology, dealing with physical biochemistry of the various proteins from a mechanistic point of view and relates mainly to the structure and function modelling studies and the effect of one on the other. Proteomics, on the other hand, involves systems biology, dealing with multiprotein systems and characterizing the behaviour of the whole system.
Measurement of gene expression is possible using various techniques; however, study of proteomics plays an important role considering the instability of the mRNAs preventing the formation of proteins as well as the regulatory functions of the different proteins in the biological and molecular mechanisms within the body. The gene expression can be measured by the use of cDNA as well as microarray system. Analysis of proteome is a complex task owing to the presence of posttranslational modification in proteins and also the fact that protein recognition is not based on sequence unlike oligonucleotides. Hence, special tools have been developed for proteomics such as
i)databases of protein, EST and genome sequence Mass spectrometry (MS),
ii)Mass Spectrometry (MS)
iii)collection of software that is capable of comparing the MS data with the protein sequence database, and
iv)protein separation technology
Analytical proteomics has become an emerging field in science. The identification of different proteins within the cell and their characterization is gaining importance even in medical field. The analysis of the whole protein is somewhat difficult. Hence, the tools for proteomics utilize different approaches for proper protein analysis. The protein is firstly converted to peptides and the sequence of the peptides is analysed. The sequence of the peptides is then matched with the sequence in the database to identify the proteins. The main problem in proteomics is the presence of a protein mixture in the biological sample. The protein analysis with the use of mixture is difficult; hence, the separation of the proteins is essential. The separation techniques involve the use of SDS-PAGE, which may be one-dimensional (1D) or two-dimensional (2D), High Performance Liquid Chromatography (HPLC). Proteins have also been analysed by digesting them and then carrying out separation using capillary electrophoresis or Isoelectric focusing (IEF). However, the protein separation by 2D SDS-PAGE followed by digestion into peptide fragments has emerged to be the better approach in analytical proteomics, due to numerous advantages offered by 2D SDS-PAGE. The proteins are digested using various proteases, which cleave at specific amino acids, thereby helping in the analysis with MS. Two types of instruments have been used for proteomics study: the MALDI-TOF and the ESI-tandem MS. Although, both the instruments work on completely different principles, they provide complementary information, hence both serve definite unique purpose. Peptide mass fingerprinting is a protein identification method used in high throughput proteomic study. In this method, the proteins are digested using trypsin and mass is analysed using MALDI-TOF. However, the difficulty in differentiation of homologous proteins and the similar proteins from different species limit the use of the method.
The main four applications of proteomics are:- Mining, protein expression profiling, protein network mapping and mapping of protein modifications. Mining refers to the identification of the proteins in a given sample i.e. the composition of the proteome is identified from the gene expression data from microarrays. Protein expression profiling is the identification of protein composition specific for a particular state of an organism or as a function to the effect of a drug or any other stimulus. Protein network mapping refers to the study of the interactions of various proteins in the functional network within the body and gives detailed information about the proteins in any signal transduction pathway. Mapping of protein modifications involves the study and identification of the nature and specificity of the posttranslational modification in a given protein. The development of protein arrays is under progress and if found successful, will create a great impact in the field of proteomics.
by priyasaravanan_1406 at 10-10-2012, 07:54 PM
1 comments
The bacterium Escherichia coli (E. coli) are one among the other microorganisms constituting the micro flora of the gut of the warm blooded animals including humans. These are called as beneficial microorganisms which are harmless. But the infection caused by a particular strain of E. coli (O157:H7) masks the beneficial effect of the normal E. coli bacteria and it is always seen as an organism of threat by many. Actually speaking the unique characteristics of the E. coli bacteria makes them an important tool in biotechnology industries and it is the most preferred organism by the researchers to perform recombinant technology (gene cloning) based experiments.
Scanning the unique features of the bacterium making it important in the field of biotechnology answers the query on its significance. The simple genome of the E. coli bacteria, the rate of growth, easy to handle, complete gene sequence, the competency as a host, simple cultivation procedure and its ability to grow under both aerobic and anaerobic condition distinguishes this bacteria from others in selection procedure for an experiment.
The genome of the E. coli bacteria is very crisp and simple with only 4400 genes, easy to study and understand. The ability of the bacteria to multiply drastically producing a generation in 1200 seconds under suitable growth condition dragged the attention of the researchers. Coming to the safety in handling the organisms, except for the particular harmful strain (O157:H7), the normal organism from the flora of the gut is safe to handle under suitable microbiological environment. The first completely sequenced genome is an additional feather in the cap of E. coli making the bacteria easier to use in recombinant DNA technology which involves nothing but the ultimate expression of proteins. Also the competence of the E. coli bacteria as a host for foreign DNAs and simple laboratory procedure to cultivate and adaptability to both aerobic and anaerobic environment made the E. coli bacteria a pioneer in the field of biotechnology.
Even before the application of the rDNA technology, the first industrial application of E. coli being the production of the amino acid threonine in the year 1961 just by exposing the organism to mutagens resulting in various mutants which were screened for the desired type of mutant enabling the synthesis of the amino acid threonine and those organisms were isolated and used for large scale production.
The process of gene cloning in E. coli involves series of steps like isolation of the desired DNA and ligasing it to a suitable vector resulting in the production recombinant molecules. These molecules are screened for the expression of the desired gene and then the selected molecules are passed on to the E. coli which express the desired gene. The types of vectors used may be either a plasmid or a cosmid or a phage and the various methods which allow the vector to enter the bacteria are transformation, transfection and transduction. Thus the genetically modified E. coli bacteria made its way into industrial biotechnology.
The genetically engineered E. coli bacteria were employed in the production of human insulin by successfully introducing the human gene responsible for insulin production into the gene sequence of the E. coli bacteria and cultivating the modified bacteria under suitable laboratory environment. Then the insulin is extracted from the cells and purified and used in humans. Also human growth hormone is produced using genetically modified E. coli bacteria.
Also there is evidence of biofuel production by using the genetically modified E. coli. The ability of the modified bacteria to convert the cellulose structure into sugars is the theory behind the production of biofuel using E. coli. The ideal character of genetically modified E. coli in producing hydrogen was discovered by a Texas scientist and he applied this principle in generating a fuel cell and proving E. coli as a house of power generation.
The fully identified gene sequence and the ability to make the gene construction in the vectors directly and a very good transformation rate of E. coli are the salient features enabled scientists to develop specific antibody molecules which will be a promising field to humans on extension.
In an effort to lower the production cost, genetically engineered E. coli were used as an alternative method in the production of the amino acid tryptophan with wide medicinal application. Also scientists from Cambridge University are on their way in developing a bio sensor E. coli to detect the presence of toxic elements in water and air. Also by extending this research, they promise the use of genetically engineered E. coli (called as E. chromi) in identifying various diseases like cancer and stomach ulcer by 2039.
Scanning the unique features of the bacterium making it important in the field of biotechnology answers the query on its significance. The simple genome of the E. coli bacteria, the rate of growth, easy to handle, complete gene sequence, the competency as a host, simple cultivation procedure and its ability to grow under both aerobic and anaerobic condition distinguishes this bacteria from others in selection procedure for an experiment.
The genome of the E. coli bacteria is very crisp and simple with only 4400 genes, easy to study and understand. The ability of the bacteria to multiply drastically producing a generation in 1200 seconds under suitable growth condition dragged the attention of the researchers. Coming to the safety in handling the organisms, except for the particular harmful strain (O157:H7), the normal organism from the flora of the gut is safe to handle under suitable microbiological environment. The first completely sequenced genome is an additional feather in the cap of E. coli making the bacteria easier to use in recombinant DNA technology which involves nothing but the ultimate expression of proteins. Also the competence of the E. coli bacteria as a host for foreign DNAs and simple laboratory procedure to cultivate and adaptability to both aerobic and anaerobic environment made the E. coli bacteria a pioneer in the field of biotechnology.
Even before the application of the rDNA technology, the first industrial application of E. coli being the production of the amino acid threonine in the year 1961 just by exposing the organism to mutagens resulting in various mutants which were screened for the desired type of mutant enabling the synthesis of the amino acid threonine and those organisms were isolated and used for large scale production.
The process of gene cloning in E. coli involves series of steps like isolation of the desired DNA and ligasing it to a suitable vector resulting in the production recombinant molecules. These molecules are screened for the expression of the desired gene and then the selected molecules are passed on to the E. coli which express the desired gene. The types of vectors used may be either a plasmid or a cosmid or a phage and the various methods which allow the vector to enter the bacteria are transformation, transfection and transduction. Thus the genetically modified E. coli bacteria made its way into industrial biotechnology.
The genetically engineered E. coli bacteria were employed in the production of human insulin by successfully introducing the human gene responsible for insulin production into the gene sequence of the E. coli bacteria and cultivating the modified bacteria under suitable laboratory environment. Then the insulin is extracted from the cells and purified and used in humans. Also human growth hormone is produced using genetically modified E. coli bacteria.
Also there is evidence of biofuel production by using the genetically modified E. coli. The ability of the modified bacteria to convert the cellulose structure into sugars is the theory behind the production of biofuel using E. coli. The ideal character of genetically modified E. coli in producing hydrogen was discovered by a Texas scientist and he applied this principle in generating a fuel cell and proving E. coli as a house of power generation.
The fully identified gene sequence and the ability to make the gene construction in the vectors directly and a very good transformation rate of E. coli are the salient features enabled scientists to develop specific antibody molecules which will be a promising field to humans on extension.
In an effort to lower the production cost, genetically engineered E. coli were used as an alternative method in the production of the amino acid tryptophan with wide medicinal application. Also scientists from Cambridge University are on their way in developing a bio sensor E. coli to detect the presence of toxic elements in water and air. Also by extending this research, they promise the use of genetically engineered E. coli (called as E. chromi) in identifying various diseases like cancer and stomach ulcer by 2039.
by Ishani7 at 10-10-2012, 06:57 PM
4 comments
Tumor inducing plasmids (Ti Plasmids) are double stranded circular DNA present in Agrobacterium tumefaciens. This article gives you complete information of these Ti Plasmids.
Agrobacterium is a gram negative soil bacterium which infects over 3000 dicots and causes crown gall disease at the collar region. This plasmid is denatured at higher temperatures and loses tumorgenic properties. Ti plasmid encode for enzymes for catabolism of opines such as permease and oxidase.
Ti plasmid ranges from 180-205kb in size. It has T DNA which is of 20kb and in addition it has several genes such as vir genes for virulence, ori gene for origin of replication, tra genes for transfer and genes for opine synthesis. Virulence genes are responsible for the transfer of T DNA into the host cell and integration of T DNA with host genome. Opines are derivatives of amino acids which are of two types; octopine and nopaline. Octopine is formed with two amino acids; Arginine and Alanine. Nopaline is made up of Arginine and Glutamine. Octopine and nopaline are not found in healthy plant tissues. The opines are catabolized and used as the energy source by the bacterium. A. tumefaciens is able to divert the metabolic resources of the host plant to the synthesis of opines which are of no apparent benefit to the plant. But they provide sustenance to the bacterium. During the infection through a wound, the plant cells begin to proliferate and form tumors and the plant tissues begin to synthesize opines.
Ti plasmids are classified based on the type of opines they produce in the host cell during infection. Almost all Ti plasmids have identical structure except in their sequence for opine metabolism. Octopine Ti plasmids produce Octopine ( C9H18N4O4). Tra genes encode proteins necessary for transfer of T DNA into the host. The Inc locus in octopine plasmids causes incompatibility of the plasmid in the bacterium. Shi and Roi sequences regulates shoot induction and root induction respectively. Nopaline Ti plasmids produces an opine called as nopaline ( C9H16N4O6).
T DNA is region of Ti plasmids common to both octopine and nopaline plasmids. But generally T DNA segment of Octopine plasmids is shorter than in Nopaline plasmids. In some octipine Ti plasmids, T DNA occurs in two segments. The left segment with 13kb in length and contains information for the synthesis of growth hormones and a sequence for opine synthesis. The right segment does not participate in tumor formation and maintenance.
Ti plasmids have a single repeated sequence at both ends of T DNA. This sequence is called as the bordered sequence. These two sequences act as sites during the transfer of Ti plasmid into the plant genome. It is found that removal of left bordered sequence doesn’t cause considerable change in tumor induction in the infected tissues. But the removal of right border sequence from T DNA results in failure of tumor induction. T DNA encode for the production of growth hormones like Cytokinin and Auxin which is necessary for tumor induction.
Vir region contains eight operons; Vir A, Vir B, Vir C, Vir D, Vir E, Vir F, Vir G and Vir H which together span about 40kb of DNA. This region mediates the transfer of T DNA into plant genome. The genes of vir region are not transferred by themselves, they only induce the transfer. The bordered sequences are essential for the transfer. Vir A and Vir G genes regulate Vir operon. Vir region is activated by the phenolic compounds, namely Acetosyringone and alpha hydroxy acetosyringone produces by plant wounds. These bind to Vir A proteins activates Vir G gene by phosphorylation which in turn activates other genes. Vir D proteins together with Vir D proteins participate in the formation of conjugal tube formation between the bacterial cell and plant tissue during the infection process.
In transferring gene of interest to Ti plasmid, an intermediate vector is used such as pBR 322. T DNA portion of the Ti plasmid is separated. T DNA is inserted into the pBR 322 vector which results in formation of a shuttle vector. This shuttle vector can replicate in E. coli and in Agrobacterium.
Ti plasmids serve as ideal vectors for plant genetic engineering as it has the capability of transferring gene of interest into the target site with a high efficiency. It is easy to screen recombinant cells as marker genes are present.
Agrobacterium is a gram negative soil bacterium which infects over 3000 dicots and causes crown gall disease at the collar region. This plasmid is denatured at higher temperatures and loses tumorgenic properties. Ti plasmid encode for enzymes for catabolism of opines such as permease and oxidase.
Ti plasmid ranges from 180-205kb in size. It has T DNA which is of 20kb and in addition it has several genes such as vir genes for virulence, ori gene for origin of replication, tra genes for transfer and genes for opine synthesis. Virulence genes are responsible for the transfer of T DNA into the host cell and integration of T DNA with host genome. Opines are derivatives of amino acids which are of two types; octopine and nopaline. Octopine is formed with two amino acids; Arginine and Alanine. Nopaline is made up of Arginine and Glutamine. Octopine and nopaline are not found in healthy plant tissues. The opines are catabolized and used as the energy source by the bacterium. A. tumefaciens is able to divert the metabolic resources of the host plant to the synthesis of opines which are of no apparent benefit to the plant. But they provide sustenance to the bacterium. During the infection through a wound, the plant cells begin to proliferate and form tumors and the plant tissues begin to synthesize opines.
Ti plasmids are classified based on the type of opines they produce in the host cell during infection. Almost all Ti plasmids have identical structure except in their sequence for opine metabolism. Octopine Ti plasmids produce Octopine ( C9H18N4O4). Tra genes encode proteins necessary for transfer of T DNA into the host. The Inc locus in octopine plasmids causes incompatibility of the plasmid in the bacterium. Shi and Roi sequences regulates shoot induction and root induction respectively. Nopaline Ti plasmids produces an opine called as nopaline ( C9H16N4O6).
T DNA is region of Ti plasmids common to both octopine and nopaline plasmids. But generally T DNA segment of Octopine plasmids is shorter than in Nopaline plasmids. In some octipine Ti plasmids, T DNA occurs in two segments. The left segment with 13kb in length and contains information for the synthesis of growth hormones and a sequence for opine synthesis. The right segment does not participate in tumor formation and maintenance.
Ti plasmids have a single repeated sequence at both ends of T DNA. This sequence is called as the bordered sequence. These two sequences act as sites during the transfer of Ti plasmid into the plant genome. It is found that removal of left bordered sequence doesn’t cause considerable change in tumor induction in the infected tissues. But the removal of right border sequence from T DNA results in failure of tumor induction. T DNA encode for the production of growth hormones like Cytokinin and Auxin which is necessary for tumor induction.
Vir region contains eight operons; Vir A, Vir B, Vir C, Vir D, Vir E, Vir F, Vir G and Vir H which together span about 40kb of DNA. This region mediates the transfer of T DNA into plant genome. The genes of vir region are not transferred by themselves, they only induce the transfer. The bordered sequences are essential for the transfer. Vir A and Vir G genes regulate Vir operon. Vir region is activated by the phenolic compounds, namely Acetosyringone and alpha hydroxy acetosyringone produces by plant wounds. These bind to Vir A proteins activates Vir G gene by phosphorylation which in turn activates other genes. Vir D proteins together with Vir D proteins participate in the formation of conjugal tube formation between the bacterial cell and plant tissue during the infection process.
In transferring gene of interest to Ti plasmid, an intermediate vector is used such as pBR 322. T DNA portion of the Ti plasmid is separated. T DNA is inserted into the pBR 322 vector which results in formation of a shuttle vector. This shuttle vector can replicate in E. coli and in Agrobacterium.
Ti plasmids serve as ideal vectors for plant genetic engineering as it has the capability of transferring gene of interest into the target site with a high efficiency. It is easy to screen recombinant cells as marker genes are present.
by Ishani7 at 10-10-2012, 05:46 PM
3 comments
Mutations are genetic changes or modifications caused by chemical and physical mutagens. Mutations can results from modification of a single base or few bases. However this can result in change or modification of a phenotypic character which can be used to recognize them. This feature is widely used in DNA recombinant technology. Plasmid vectors carry genes for drug resistance, toxin production which can be used to distinguish recombinants. When genes of interest are inserted into the plasmid, the reading frame for the marker genes can be altered. This results in mutants who can be identified using special chemicals/ media.
AMES test is one such method to identify mutants of Salmonella typhimurium that cannot produce Histidine. This mutant stain can be cultured only when Histidine is present in the basic medium. This is the standard culture used for testing chemical mutagens. The chemical mutagen is loaded into a well in the centre of a culture plate of inoculated with Salmonella typhimurium in a medium lacking Histidine. The chemical diffuses into the medium. A growth indicates that the chemical has induced a mutation in Histidine- stain converting it to Histidine +. Depending on the position of the colony relative to the well containing the chemical, the degree of resistance varies. Colonies growing closer to the well are quite resistant and colonies growing at the periphery indicate that the chemical even at a low concentration can induce mutation. This test has its application in pharmaceutical industry to test the effect of drugs; whether it’s a mutagen or not.
In replica plating method to screen mutants, the organism is subjected to radiation or exposed to chemical to induce the mutation. The mutants can be identified by a reduction in the colony size or change in pigmentation etc. Sub culture is made by replica plating the master culture. The sub cultured plate is subjected to mutation and incubated for growth. Then the plate subjected to mutation is replica plated onto a fresh medium and incubated to observe phenotypic variations. This method can be used to identify the dosage of radiation or chemicals required to cause mutations. If this is repeated with different dosage levels, the finally left colony will be having most resistant cells for the particular mutagen.
Gradient method is used to study the effect of chemical mutagens on bacteria. A medium containing two different concentrations are prepared separately and poured over the same plate in a slanting position. First the medium with lower concentration of the chemical is poured onto the plate in a slanting position and allowed to solidify. Then the medium with higher concentration of the chemical is poured onto the plate. The plate is inoculated and observed for growth. This is repeated till there is no growth at higher concentration to identify the effective concentration.
Blue white selection is a widely used method in screening recombinants in cloning. This is based on the gene product of lac z gene. The plasmid vectors contain this gene which produces β galactosidase enzyme. When a gene is inserted close to lac z gene, the reading frame will be distorted and the gene is inactivated. So the transformed cells will not produce this enzyme and are called competent cells. After the recombination, the bacterial cells are grown in a medium containing X gal (5-bromo-4-chloro-indolyl-β-D-galactopyranoside) and IPTG (Isopropyl β-D-1-thiogalactopyranoside). IPTG acts as the inducer for lac z gene and enhance the production of β galactosidase. When it is produced, combines with X gal to form a blue colour complex called 5,5'-dibromo-4,4'-dichloro-indigo which is insoluble. The transformed colonies will appear white in colour and non- transformed cells will appear blue in colour. This method is also called as insertional inactivation of lac z gene.
Hybridization techniques are widely used to identify recombinants. This is based on the ability of nucleic acids hybridize with complementary DNA. The transformed cells are transferred on to a nitrocellulose membrane which is subjected to cell lysis. The double stranded DNA is converted to single stranded DNA and immobilized on the membrane. Then it is treated with radiolabelled probes complementary to target DNA. If the desired DNA is present, the probes will be hybridized which can be detected by autoradiography.
Apart from these methods, immunochemical methods are used to detect protein products to screen recombinants.
AMES test is one such method to identify mutants of Salmonella typhimurium that cannot produce Histidine. This mutant stain can be cultured only when Histidine is present in the basic medium. This is the standard culture used for testing chemical mutagens. The chemical mutagen is loaded into a well in the centre of a culture plate of inoculated with Salmonella typhimurium in a medium lacking Histidine. The chemical diffuses into the medium. A growth indicates that the chemical has induced a mutation in Histidine- stain converting it to Histidine +. Depending on the position of the colony relative to the well containing the chemical, the degree of resistance varies. Colonies growing closer to the well are quite resistant and colonies growing at the periphery indicate that the chemical even at a low concentration can induce mutation. This test has its application in pharmaceutical industry to test the effect of drugs; whether it’s a mutagen or not.
In replica plating method to screen mutants, the organism is subjected to radiation or exposed to chemical to induce the mutation. The mutants can be identified by a reduction in the colony size or change in pigmentation etc. Sub culture is made by replica plating the master culture. The sub cultured plate is subjected to mutation and incubated for growth. Then the plate subjected to mutation is replica plated onto a fresh medium and incubated to observe phenotypic variations. This method can be used to identify the dosage of radiation or chemicals required to cause mutations. If this is repeated with different dosage levels, the finally left colony will be having most resistant cells for the particular mutagen.
Gradient method is used to study the effect of chemical mutagens on bacteria. A medium containing two different concentrations are prepared separately and poured over the same plate in a slanting position. First the medium with lower concentration of the chemical is poured onto the plate in a slanting position and allowed to solidify. Then the medium with higher concentration of the chemical is poured onto the plate. The plate is inoculated and observed for growth. This is repeated till there is no growth at higher concentration to identify the effective concentration.
Blue white selection is a widely used method in screening recombinants in cloning. This is based on the gene product of lac z gene. The plasmid vectors contain this gene which produces β galactosidase enzyme. When a gene is inserted close to lac z gene, the reading frame will be distorted and the gene is inactivated. So the transformed cells will not produce this enzyme and are called competent cells. After the recombination, the bacterial cells are grown in a medium containing X gal (5-bromo-4-chloro-indolyl-β-D-galactopyranoside) and IPTG (Isopropyl β-D-1-thiogalactopyranoside). IPTG acts as the inducer for lac z gene and enhance the production of β galactosidase. When it is produced, combines with X gal to form a blue colour complex called 5,5'-dibromo-4,4'-dichloro-indigo which is insoluble. The transformed colonies will appear white in colour and non- transformed cells will appear blue in colour. This method is also called as insertional inactivation of lac z gene.
Hybridization techniques are widely used to identify recombinants. This is based on the ability of nucleic acids hybridize with complementary DNA. The transformed cells are transferred on to a nitrocellulose membrane which is subjected to cell lysis. The double stranded DNA is converted to single stranded DNA and immobilized on the membrane. Then it is treated with radiolabelled probes complementary to target DNA. If the desired DNA is present, the probes will be hybridized which can be detected by autoradiography.
Apart from these methods, immunochemical methods are used to detect protein products to screen recombinants.
by BojanaL at 10-10-2012, 04:59 PM
0 comments
Biotechnology is multidisciplinary field that can be divided into 4 more specific areas, using color coding system. Red biotechnology is dedicated to design as much products and devices related to the medical field as possible. Green is focused on agricultural improvements and environmental protection. Blue is using ocean resources to develop various products (from food to fuels…) and white is focused on industrial processes. Out of 4 fields mentioned - red biotechnology is the most profitable: billion dollars are spent each year for research and development in medical field.
Here’s the list of 10 most innovative biotech companies and short info on their main research areas.
Life technologies
Life technologies is headquartered in Carlsbad, California. It’s founded in 2008, have ~11 000 employees and is highly profitable. 2011 revenue was 3.7 billion dollars. They are developing lab equipment for all kind of genetic testing (Applied Biosystems), products for isolation, quantification and amplifications of RNA (Ambion), biologic drug production associated materials (Gibco), DNA and biology associated products (Invitrogen), molecular probes under the same brand name, products for purification, separation and analysis of proteins (Novex), products used for gene expression experiments (TaqMan) and ion semiconductor DNA sequencing system (Ion Torrent). They have offices in more than 60 countries worldwide.
Genentech
Genentech is pioneer of biotechnology industry. Founded in 1976 with headquarter in South San Francisco. It has over 11 000 employees and as from 2009 it is wholly owned subsidiary of Roche. All scientist, researchers and post-docs are focused on 5 main research areas: oncology, neuroscience, tissue growth and repair, immunology and infectious diseases.
Bug Agentes Biologicos
Company is founded in 1999 and based in Piracicaba, Brazil. It’s focused on development of natural pesticide replacements. Main products are predatory insect eggs and parasitoids used for crop protection. Those are mainly used for soy field’s protection.
Amyris
Amyris is founded in 2003 and it’s focused on providing sustainable alternatives to petroleum derived products. Plant sugar is starting point. It undergoes industrial conversion into various hydrocarbons that will be used for renewable products development later used in cosmetic and polymer industry, for lubricants, flavors….even for jet fuel. Headquarter is in Emeryville, California.
GE (GE Healthcare)
GE Healthcare is only division of GE business that is headquartered outside the USA, in Little Chalfont, United Kingdom. It’s founded in 2004 and it’s focused on medical imaging and diagnostics (equipment they are manufacturing is ranging from X rays to magnetic resonance), drug discovery, pharmaceutical manufacturing…
Diagnostics for all
Diagnostics for all is non-profit organization founded in 2007. Idea was to help solve medical issues in developing and resource poor countries all over the world by creating a simple and cheap diagnostic device - patterned paper. Small piece of paper covered with biological and chemical assays reagent is cheap and fast way to test yourself. By applying small amount of biological fluids, assay zone is changing the color that should be compared with reference color on the device. Money they need for testing, research and manufacture is provided through public donations.
The Plant
The Plant is building in Chicago most famous for being first vertical farm. Vertical farming is becoming very popular as the number of people living in urban area is growing rapidly. The Plant produces aquaponic vegetables. Fertilizers (necessary for proper plant development) are derived from algae that are consuming waste. Idea is to create building that will have net zero energy and waste (level of produced and consumed energy and waste should be equal).
Cellular Dynamics International
Cellular Dynamics International is founded in 2004 with headquarter in Madison, Wisconsin. Company is manipulating with stem cells to produce tissues of various kinds that will be used for drug development process, for tissue engineering or organ regeneration purposes. Roche is using iCell for drug screening.
Humacyte
Humacyte is founded in 2004 in Morrisville, North Carolina. Research is focused on vascular diseases and soft tissue repair application (vein graft development). Human, extracellular matrix derived tissue would help decrease inflammation, clotting and thrombosis, foreign body response after implantation in the body and would demand fewer surgical interventions that are necessary when conventional methods are used.
Harvard Bioscience
Harvard Bioscience is founded over 100 years ago in Holliston, Massachusetts. Company is manufacturing different kind of instruments and equipment that is used in life science and regenerative medicine fields (such as molecular, cellular, and physiology research). Some of the most interesting HB products are artificial trachea, synthetic windpipe and organs made out of body’s own cells. They have 20 wholly owned subsidiaries.
Now when you know their names and research goals – you just have to choose one that suits you the best.
Here’s the list of 10 most innovative biotech companies and short info on their main research areas.
Life technologies
Life technologies is headquartered in Carlsbad, California. It’s founded in 2008, have ~11 000 employees and is highly profitable. 2011 revenue was 3.7 billion dollars. They are developing lab equipment for all kind of genetic testing (Applied Biosystems), products for isolation, quantification and amplifications of RNA (Ambion), biologic drug production associated materials (Gibco), DNA and biology associated products (Invitrogen), molecular probes under the same brand name, products for purification, separation and analysis of proteins (Novex), products used for gene expression experiments (TaqMan) and ion semiconductor DNA sequencing system (Ion Torrent). They have offices in more than 60 countries worldwide.
Genentech
Genentech is pioneer of biotechnology industry. Founded in 1976 with headquarter in South San Francisco. It has over 11 000 employees and as from 2009 it is wholly owned subsidiary of Roche. All scientist, researchers and post-docs are focused on 5 main research areas: oncology, neuroscience, tissue growth and repair, immunology and infectious diseases.
Bug Agentes Biologicos
Company is founded in 1999 and based in Piracicaba, Brazil. It’s focused on development of natural pesticide replacements. Main products are predatory insect eggs and parasitoids used for crop protection. Those are mainly used for soy field’s protection.
Amyris
Amyris is founded in 2003 and it’s focused on providing sustainable alternatives to petroleum derived products. Plant sugar is starting point. It undergoes industrial conversion into various hydrocarbons that will be used for renewable products development later used in cosmetic and polymer industry, for lubricants, flavors….even for jet fuel. Headquarter is in Emeryville, California.
GE (GE Healthcare)
GE Healthcare is only division of GE business that is headquartered outside the USA, in Little Chalfont, United Kingdom. It’s founded in 2004 and it’s focused on medical imaging and diagnostics (equipment they are manufacturing is ranging from X rays to magnetic resonance), drug discovery, pharmaceutical manufacturing…
Diagnostics for all
Diagnostics for all is non-profit organization founded in 2007. Idea was to help solve medical issues in developing and resource poor countries all over the world by creating a simple and cheap diagnostic device - patterned paper. Small piece of paper covered with biological and chemical assays reagent is cheap and fast way to test yourself. By applying small amount of biological fluids, assay zone is changing the color that should be compared with reference color on the device. Money they need for testing, research and manufacture is provided through public donations.
The Plant
The Plant is building in Chicago most famous for being first vertical farm. Vertical farming is becoming very popular as the number of people living in urban area is growing rapidly. The Plant produces aquaponic vegetables. Fertilizers (necessary for proper plant development) are derived from algae that are consuming waste. Idea is to create building that will have net zero energy and waste (level of produced and consumed energy and waste should be equal).
Cellular Dynamics International
Cellular Dynamics International is founded in 2004 with headquarter in Madison, Wisconsin. Company is manipulating with stem cells to produce tissues of various kinds that will be used for drug development process, for tissue engineering or organ regeneration purposes. Roche is using iCell for drug screening.
Humacyte
Humacyte is founded in 2004 in Morrisville, North Carolina. Research is focused on vascular diseases and soft tissue repair application (vein graft development). Human, extracellular matrix derived tissue would help decrease inflammation, clotting and thrombosis, foreign body response after implantation in the body and would demand fewer surgical interventions that are necessary when conventional methods are used.
Harvard Bioscience
Harvard Bioscience is founded over 100 years ago in Holliston, Massachusetts. Company is manufacturing different kind of instruments and equipment that is used in life science and regenerative medicine fields (such as molecular, cellular, and physiology research). Some of the most interesting HB products are artificial trachea, synthetic windpipe and organs made out of body’s own cells. They have 20 wholly owned subsidiaries.
Now when you know their names and research goals – you just have to choose one that suits you the best.
by Ishani7 at 10-10-2012, 03:52 PM
2 comments
DNA, our genetic material provides identity to our characters. Being the universal genetic material for higher organisms, it is almost similar in one organism. This method of identification is known as DNA sequencing which is widely used in taxonomic studies etc. DNA sequencing is different from DNA fingerprinting as it involves determining base sequence rather than comparing DNA fragments.
DNA is made up of thousands of nucleotides which in triplet codons encode specific proteins. Order of nucleotides in DNA is called the DNA sequence which is commoner in one organism. There are specific regions common to one type of organism. As the total sequence is huge, only the specific region required to identify one type of organism is sequenced for example, ITS region for fungi, 16s r RNA region for bacteria etc. These regions are amplified by using specific primers prior to sequencing. Species specific primers which are part of these regions corresponding to unique products of different species can be used to generate more accurate results.
Prior to DNA sequencing, DNA of interest is isolated, purified and amplified by Polymerase Chain Reaction (PCR). PCR results in millions of copies of the DNA fragment to be sequenced. Two methods are used in DNA sequencing; Chain termination method/Sanger Coulson Method and Chemical Degradation Method/ Maxam-Gillbert method.
Sanger Coulson method requires the DNA to be sequenced to be cloned into a vector (M13). In Chain termination method, strand synthesis is done with the help of modified DNA polymerase which is called as kleno fragment with polymerase activity. This strand synthesis involves PCR reactions and different from usual DNA synthesis as this makes use of di-deoxynucleotides which lacks 3’ Hydroxyl group. When this special type of nucleotides is used, after this nucleotide other nucleotides cannot be added which results in chain termination. Fragments of different length can be obtained. Four vials corresponding to four types of nucleotides consisting of Adenine, Guanine, Cytosine and Uracil. Only one type of dideoxy nucleotide is added to one vial. Out of the four deoxynucleotides one should be radiolabelled with P32 or S35 isotopes. In each vial, stand synthesis and amplification takes place by PCR. After the reaction, the DNA fragments are separated by gel electrophoresis. This gel is incorporated with urea which makes double stranded DNA into single stranded DNA. Since the difference in length between two fragments can be small as a nucleotide, the electrophoresis process should be well controlled. The amplified products in four vials are run separately and based on the position of the band the sequence can be determined.
In chemical degradation method, primers are not required as it doesn’t involve DNA synthesis. And this method does not require the DNA to be cloned into a vector. It involves chemicals to degrade DNA. The double stranded DNA to be sequenced is labeled with a radioactive phosphorous group at 5’ end using the enzyme polynucleotide kinase. Dimethyl sulphate is added to the labeled DNA and heated to obtain single stranded DNA. Generally assuming that one template strand contains more purines and is heavier, the other strand will move faster in a gel during separation. The amplified DNA samples are taken in four vials.
In the first vial, Dimethyl sulphate brings about a chemical modification of a specific nucleotide. It acts on Guanine and makes a nucleophillic attack 7th Nitrogen and it becomes unstable. This instability leads to breakage of DNA strand at that point. By adding piperidine, unstable Guanine is removed. Dimethyl sulphate in acidic medium is used for the second tube. This will attack purines; Adenine and Guanine, and chemically modify the bases. In the third tube, hydrazine is added along with piperidine. Hydrazine interacts with Cytosine and brings about a chemical change. Hydrazine in an alkaline medium is used for the fourth tube followed by piperidine which reacts with pyrimidines. Only a single break is made in one strand. These tubes treated with different chemicals are subjected to gel electrophoresis.
DNA fingerprinting, in contrast compare the variable number of tandem repeats (VNTR) in human DNA for identification. These are non-coding sequences of which number of repetitions is unique to a person. This is widely used in forensic investigations and paternity testing.
DNA is made up of thousands of nucleotides which in triplet codons encode specific proteins. Order of nucleotides in DNA is called the DNA sequence which is commoner in one organism. There are specific regions common to one type of organism. As the total sequence is huge, only the specific region required to identify one type of organism is sequenced for example, ITS region for fungi, 16s r RNA region for bacteria etc. These regions are amplified by using specific primers prior to sequencing. Species specific primers which are part of these regions corresponding to unique products of different species can be used to generate more accurate results.
Prior to DNA sequencing, DNA of interest is isolated, purified and amplified by Polymerase Chain Reaction (PCR). PCR results in millions of copies of the DNA fragment to be sequenced. Two methods are used in DNA sequencing; Chain termination method/Sanger Coulson Method and Chemical Degradation Method/ Maxam-Gillbert method.
Sanger Coulson method requires the DNA to be sequenced to be cloned into a vector (M13). In Chain termination method, strand synthesis is done with the help of modified DNA polymerase which is called as kleno fragment with polymerase activity. This strand synthesis involves PCR reactions and different from usual DNA synthesis as this makes use of di-deoxynucleotides which lacks 3’ Hydroxyl group. When this special type of nucleotides is used, after this nucleotide other nucleotides cannot be added which results in chain termination. Fragments of different length can be obtained. Four vials corresponding to four types of nucleotides consisting of Adenine, Guanine, Cytosine and Uracil. Only one type of dideoxy nucleotide is added to one vial. Out of the four deoxynucleotides one should be radiolabelled with P32 or S35 isotopes. In each vial, stand synthesis and amplification takes place by PCR. After the reaction, the DNA fragments are separated by gel electrophoresis. This gel is incorporated with urea which makes double stranded DNA into single stranded DNA. Since the difference in length between two fragments can be small as a nucleotide, the electrophoresis process should be well controlled. The amplified products in four vials are run separately and based on the position of the band the sequence can be determined.
In chemical degradation method, primers are not required as it doesn’t involve DNA synthesis. And this method does not require the DNA to be cloned into a vector. It involves chemicals to degrade DNA. The double stranded DNA to be sequenced is labeled with a radioactive phosphorous group at 5’ end using the enzyme polynucleotide kinase. Dimethyl sulphate is added to the labeled DNA and heated to obtain single stranded DNA. Generally assuming that one template strand contains more purines and is heavier, the other strand will move faster in a gel during separation. The amplified DNA samples are taken in four vials.
In the first vial, Dimethyl sulphate brings about a chemical modification of a specific nucleotide. It acts on Guanine and makes a nucleophillic attack 7th Nitrogen and it becomes unstable. This instability leads to breakage of DNA strand at that point. By adding piperidine, unstable Guanine is removed. Dimethyl sulphate in acidic medium is used for the second tube. This will attack purines; Adenine and Guanine, and chemically modify the bases. In the third tube, hydrazine is added along with piperidine. Hydrazine interacts with Cytosine and brings about a chemical change. Hydrazine in an alkaline medium is used for the fourth tube followed by piperidine which reacts with pyrimidines. Only a single break is made in one strand. These tubes treated with different chemicals are subjected to gel electrophoresis.
DNA fingerprinting, in contrast compare the variable number of tandem repeats (VNTR) in human DNA for identification. These are non-coding sequences of which number of repetitions is unique to a person. This is widely used in forensic investigations and paternity testing.
by Kamat2010 at 10-10-2012, 03:06 PM
0 comments
The TRESK channels have paved way for the development of potential treatments for migraine.
Migraine is a chronic neurovascular disorder characterized by severe, episodic headaches often accompanied by other symptoms like nausea, phonophobia or sensitivity to sound, photophobia or sensitivity to light, vomiting, etc. A symptom usually precedes the migraine headache, which is a transient, focal, neurological phenomenon, known as aura, which is actually loss of vision or flashes of light. The differences between the causes for the migraine with aura (MA) and the migraine without aura (MO) are not clearly known and some patients experience the symptoms of both the types of migraine.
The exact cause of the migraine was not known until few years back, but successful genetic studies have shown that MA is a genetic disorder and results from some faulty genes, which makes some people predisposed to the migraine condition. The cortical spreading depression (CSD) results in the migraine aura, which is a wave of the depolarization in the pain neurons and the glial cells followed by inactivity and spreads over the entire cortical region. The trigeminal system (TGVS) is activated by the CSD initiating headache. This projects to the brain stem, which in turn projects to the other pain centres in the brain. However, the presence of a link between CSD in MO is not known yet. It has been seen that in some cases migraine like symptoms result due to severe stress or hormonal imbalance, etc, though there is no concrete evidence to prove it.
In case of the genetic disorders, it is often seen that a combination of mutations in several genes result in the disease. However, in the study of Migraine, a genetic disease, it is seen that a defect in a single gene may result in the formation of the disease. MA is also known as Familial hemiplegic migraine. Recent studies have shown that defect in the ion channels and its transporters may be responsible for the formation of the disease. As it is known that ion channels play an important part in the excitability of a nerve, hence a defect in the ion transporters which transport ions in and out of the nerve cells may affect the excitability of the nerve. It is seen that in the migraine sufferers, the excitability of the nerves increases, thereby hinting the presence of fault in the ion channels and its transporters.
While studying the ion transporters and its genes, the latest discovery in relation to the disease has been the identification of a mutation in the TRESK gene in the family of DNA sufferers, by DNA sequencing method. The TRESK gene is responsible for the formation of the protein TWIK related spinal cord potassium channel (TRESK). The TRESK is responsible for the transmission of signals between the nerve cells. It is a potassium channel, which causes the efflux of the potassium ions from the nerve cells. It is mainly associated with the pain pathways because on stimulation, it numbs the pain and prevents the passage of pain signal between the nerve cells. Hence, it plays an important role in the action of the anaesthetics. A mutation in this gene thereby causes increased sensitivity of the nerve cells. Moreover, the TRESK is abundantly present in the trigeminal ganglion region of the brain, which is the major part associated with the transmission of the pain stimuli in the brain. The presence of mutation in this gene was noted in only one large family of migraine sufferers, while the majority of other migraine sufferers showed absence of the same. Hence, it remains to be studied if other less severe defects in the TRESK gene or defects in the genes or proteins associated with it could be a possible mechanism for migraine formation.
The discovery of drugs stimulating the TRESK channel may prove to be an effective treatment, though they may not be potent in case of complete loss of the function of the channel. Moreover, gene therapy for defective TRESK channels may also be a potential ground for research. The ongoing research on the subject may initiate better forms of treatment for the prevalent disease, though extensive, in-depth study is essential for knowing the underlying molecular mechanisms behind the formation of the disease.
Migraine is a chronic neurovascular disorder characterized by severe, episodic headaches often accompanied by other symptoms like nausea, phonophobia or sensitivity to sound, photophobia or sensitivity to light, vomiting, etc. A symptom usually precedes the migraine headache, which is a transient, focal, neurological phenomenon, known as aura, which is actually loss of vision or flashes of light. The differences between the causes for the migraine with aura (MA) and the migraine without aura (MO) are not clearly known and some patients experience the symptoms of both the types of migraine.
The exact cause of the migraine was not known until few years back, but successful genetic studies have shown that MA is a genetic disorder and results from some faulty genes, which makes some people predisposed to the migraine condition. The cortical spreading depression (CSD) results in the migraine aura, which is a wave of the depolarization in the pain neurons and the glial cells followed by inactivity and spreads over the entire cortical region. The trigeminal system (TGVS) is activated by the CSD initiating headache. This projects to the brain stem, which in turn projects to the other pain centres in the brain. However, the presence of a link between CSD in MO is not known yet. It has been seen that in some cases migraine like symptoms result due to severe stress or hormonal imbalance, etc, though there is no concrete evidence to prove it.
In case of the genetic disorders, it is often seen that a combination of mutations in several genes result in the disease. However, in the study of Migraine, a genetic disease, it is seen that a defect in a single gene may result in the formation of the disease. MA is also known as Familial hemiplegic migraine. Recent studies have shown that defect in the ion channels and its transporters may be responsible for the formation of the disease. As it is known that ion channels play an important part in the excitability of a nerve, hence a defect in the ion transporters which transport ions in and out of the nerve cells may affect the excitability of the nerve. It is seen that in the migraine sufferers, the excitability of the nerves increases, thereby hinting the presence of fault in the ion channels and its transporters.
While studying the ion transporters and its genes, the latest discovery in relation to the disease has been the identification of a mutation in the TRESK gene in the family of DNA sufferers, by DNA sequencing method. The TRESK gene is responsible for the formation of the protein TWIK related spinal cord potassium channel (TRESK). The TRESK is responsible for the transmission of signals between the nerve cells. It is a potassium channel, which causes the efflux of the potassium ions from the nerve cells. It is mainly associated with the pain pathways because on stimulation, it numbs the pain and prevents the passage of pain signal between the nerve cells. Hence, it plays an important role in the action of the anaesthetics. A mutation in this gene thereby causes increased sensitivity of the nerve cells. Moreover, the TRESK is abundantly present in the trigeminal ganglion region of the brain, which is the major part associated with the transmission of the pain stimuli in the brain. The presence of mutation in this gene was noted in only one large family of migraine sufferers, while the majority of other migraine sufferers showed absence of the same. Hence, it remains to be studied if other less severe defects in the TRESK gene or defects in the genes or proteins associated with it could be a possible mechanism for migraine formation.
The discovery of drugs stimulating the TRESK channel may prove to be an effective treatment, though they may not be potent in case of complete loss of the function of the channel. Moreover, gene therapy for defective TRESK channels may also be a potential ground for research. The ongoing research on the subject may initiate better forms of treatment for the prevalent disease, though extensive, in-depth study is essential for knowing the underlying molecular mechanisms behind the formation of the disease.
by Ishani7 at 10-10-2012, 01:16 PM
1 comments
Molecular Biological methods are dealing with isolation, amplification, modification, identification of genetic material. These procedures make use of biological tools such as enzymes, primers, plasmids etc. Most of these are isolated from microbes which are of great importance. Ability of these enzymes and other compounds to withstand different in-vitro conditions is the reason why they are used for experimental purpose.
DNA polymerase is the master blaster enzyme used in molecular methods such as Polymerase Chain Reaction (PCR). This enzyme catalyzes synthesis of DNA. This enzyme has 5’ exonuclease activity, proofreading activity additional to DNA synthesis. DNA polymerase used in vitro conditions is isolated from the bacterium Thermus aquaticus which is highly thermostable and functions optimally at the temperature range of 750C-800C.
Restriction enzymes are widely used biological tools in Molecular biology. These are known as Molecular scissors. These enzymes have the ability to cut DNA recognizing a specific sequence. There are 4 types of restriction enzymes. Type II and Type IV are used in recombinant DNA technology. Restriction enzymes are named with the bacterium of which it has been isolated and corresponding number of the restriction site. Some recognition enzymes have a separate recognition site and a cleavage site while in some both are the same. Restriction enzymes with same cleavage and restriction site are called as Isochizomers. Type II enzymes are very stable which requires Mg2+ as cofactor and shows star activity ( change in specificity). Few examples for restriction enzymes are E co RI, Pvul I, Hae III, Alu I, Hpa I.
DNA ligases have the ability to join two DNA fragments which is called as ligation of DNA. Ligation depends on the type of ends to be joined whether sticky or blunt. This enzyme is usually isolated from E. coli cultures which are infected with T4 phage for genetic engineering. T4 ligase is capable of carrying out ligation invitro conditions. DNA ligase functions optimally at 370C.
Alkaline phosphatases are another group of enzymes used in Recombinant Technology. When plasmid vector for joining a foreign DNA fragment is treated with restriction enzymes, the cohesive ends of the broken plasmids instead of joining with foreign DNA join the cohesive end of the same DNA molecules and get re-circularized. To overcome this problem, restricted plasmid is treated with alkaline phosphatase which digests the 5’ phosphoryl group so that 5’ end of foreign DNA can covalently join to 3’ end of the plasmid. This enzyme is a diametric glycoprotein made up of two identical units and isolated from E.coli.
Reverse transcriptase enzyme is isolated from Avian Myeloblastosis virus which requires Mg or Mn for initiation of reverse transcription. To obtain DNA to clone a eukaryotic gene is more complicated because these contain regions called as introns that are non-coding regions. This enzyme cut introns out of mRNA and produce intron free DNA which is called c DNA.
Plasmid vectors are closed circular double stranded extra chromosomal units and widely used in recombinant DNA technology for carrying specific genes into an organism. Plasmids are used as they have the ability to self-replication. Plasmids used in genetic engineering carry specific genes called as marker genes which enable the selection of recombinant organisms in later stages. These marker genes include antibiotic resistant genes, genes for toxin production etc. These contain restriction sites which can be cleaved with restriction enzymes and can be replaced by gene of interest. Size of a plasmid ranges from 1-200kb. Example for plasmids is Ti plasmid isolated from Agrobacterium tumefaciens.
Apart from plasmids isolated from bacteria, viruses are also used as cloning vectors due to its ability of infection. Mostly, they are used as plant vectors. Cauliflower mosaic viruses, Gemini virus, Tobacco Mosaic Virus are some viruses used. As most of the viruses contain RNA as the genetic material, gene regulation functions through production of c DNA by reverse transcription. In contrast to plasmids, viral vectors can incorporate only a small fragment of DNA. Simian Virus, Vaccinia Virus and Retro Virus are some animal vectors. Vaccinia virus is used in vaccines to produce immunogenicity.
Cosmid is a hybrid between a plasmid and a bacteriophage DNA. These contain cos sequences of bacteriophages which directs insertion of DNA. Bacteriophages are viruses that infect bacteria. Cosmid is almost similar to a plasmid which has an origin of replication, restriction sites and marker genes.
DNA polymerase is the master blaster enzyme used in molecular methods such as Polymerase Chain Reaction (PCR). This enzyme catalyzes synthesis of DNA. This enzyme has 5’ exonuclease activity, proofreading activity additional to DNA synthesis. DNA polymerase used in vitro conditions is isolated from the bacterium Thermus aquaticus which is highly thermostable and functions optimally at the temperature range of 750C-800C.
Restriction enzymes are widely used biological tools in Molecular biology. These are known as Molecular scissors. These enzymes have the ability to cut DNA recognizing a specific sequence. There are 4 types of restriction enzymes. Type II and Type IV are used in recombinant DNA technology. Restriction enzymes are named with the bacterium of which it has been isolated and corresponding number of the restriction site. Some recognition enzymes have a separate recognition site and a cleavage site while in some both are the same. Restriction enzymes with same cleavage and restriction site are called as Isochizomers. Type II enzymes are very stable which requires Mg2+ as cofactor and shows star activity ( change in specificity). Few examples for restriction enzymes are E co RI, Pvul I, Hae III, Alu I, Hpa I.
DNA ligases have the ability to join two DNA fragments which is called as ligation of DNA. Ligation depends on the type of ends to be joined whether sticky or blunt. This enzyme is usually isolated from E. coli cultures which are infected with T4 phage for genetic engineering. T4 ligase is capable of carrying out ligation invitro conditions. DNA ligase functions optimally at 370C.
Alkaline phosphatases are another group of enzymes used in Recombinant Technology. When plasmid vector for joining a foreign DNA fragment is treated with restriction enzymes, the cohesive ends of the broken plasmids instead of joining with foreign DNA join the cohesive end of the same DNA molecules and get re-circularized. To overcome this problem, restricted plasmid is treated with alkaline phosphatase which digests the 5’ phosphoryl group so that 5’ end of foreign DNA can covalently join to 3’ end of the plasmid. This enzyme is a diametric glycoprotein made up of two identical units and isolated from E.coli.
Reverse transcriptase enzyme is isolated from Avian Myeloblastosis virus which requires Mg or Mn for initiation of reverse transcription. To obtain DNA to clone a eukaryotic gene is more complicated because these contain regions called as introns that are non-coding regions. This enzyme cut introns out of mRNA and produce intron free DNA which is called c DNA.
Plasmid vectors are closed circular double stranded extra chromosomal units and widely used in recombinant DNA technology for carrying specific genes into an organism. Plasmids are used as they have the ability to self-replication. Plasmids used in genetic engineering carry specific genes called as marker genes which enable the selection of recombinant organisms in later stages. These marker genes include antibiotic resistant genes, genes for toxin production etc. These contain restriction sites which can be cleaved with restriction enzymes and can be replaced by gene of interest. Size of a plasmid ranges from 1-200kb. Example for plasmids is Ti plasmid isolated from Agrobacterium tumefaciens.
Apart from plasmids isolated from bacteria, viruses are also used as cloning vectors due to its ability of infection. Mostly, they are used as plant vectors. Cauliflower mosaic viruses, Gemini virus, Tobacco Mosaic Virus are some viruses used. As most of the viruses contain RNA as the genetic material, gene regulation functions through production of c DNA by reverse transcription. In contrast to plasmids, viral vectors can incorporate only a small fragment of DNA. Simian Virus, Vaccinia Virus and Retro Virus are some animal vectors. Vaccinia virus is used in vaccines to produce immunogenicity.
Cosmid is a hybrid between a plasmid and a bacteriophage DNA. These contain cos sequences of bacteriophages which directs insertion of DNA. Bacteriophages are viruses that infect bacteria. Cosmid is almost similar to a plasmid which has an origin of replication, restriction sites and marker genes.
by Ishani7 at 10-10-2012, 11:47 AM
3 comments
Drosophila, known as fruit fly is widely used as a model organism in genetic studies for studying mutations, inheritance patterns etc. Drosophila melanogaster is a holometabolous insect. An adult fly has three basic body parts; head, thorax and abdomen. Thorax consists of three segments with legs, winds and halters. Abdomen has 11 segments. Large number of mutations in the fruit fly influences all aspects of their development and there mutations have been subjected to molecular analysis to find how the genes control early development in Drosophila.
When a Drosophila egg has been fertilized, its diploid nucleus immediately divides nine times without division of the cytoplasm creating a single multinucleating cell. After 8th division, nuclei get scattered in the cytoplasm followed by formation of 4 polar nuclei in 10th division. In the 13th division, nuclei divides and numerous nuclei are found in the periphery. This is called syncytial blastoderm. Each of these nuclei proved to have their own cytoplasmic environment rich in microtubules. Plasma membrane invaginates and each nuclei are surrounded by a membrane, which is called as cellular blastoderms. This has about 6000 cells. Polar cells give rise to germ cells and embryo undergoes further development. Three important genes are involved in the development of Drosophila; maternal effector genes/ egg polarity genes, segmentation genes, homeotic genes.
Egg polarity genes function in axis specification. These genes act by setting up a concentration gradient of morphogens in the developing embryo. A morphogen is a protein whose concentration gradient affects the developmental fate of the surrounding region. The egg polarity genes are transcribed into mRNA in the course of egg formation in the maternal parent and this maternal mRNA are incorporated in the cytoplasm of the egg. Proteins encoded by these mRNA play an important role in axis determination. These proteins are examples of maternal inheritance as the offspring will have similar phenotype.
Like in all other insects, fruit fly has a segmented body. When axis specification has taken place, segmentation genes control the differentiation of the embryo into individual segments. About 25 genes are included in segmentation genes. They are zygotic genes whose expression is controlled by bicoid and nanos protein gradients. Gap genes in segmentation genes are involved in defining large segments of embryo. Pair rule genes define regional sections of the embryo. Segment polarity genes are involved in organization of segments. Mutations in these genes lead to absence of certain segments.
Gap genes, which are regulated by maternal genes, are involved in dividing the embryo into broad regions each containing parasegment primodia. Hunchback proteins are expressed at the anterior end. Transcription of anterior gap genes are initiated by the different concentrations of hunchback and bicoid proteins. Higher concentration of hunchback proteins results in expression of giant proteins and prevents transcription of posterior gap genes in the anterior part whereas lower hunchback concentrations result in expression of kruppel proteins. Giant gene has two methods of activation; one for anterior expression band and one for posterior expression band. After this, gap genes become stabilized and maintained by interactions between different gap gene products. Protein products of gap genes interact with neighbouring gap gene proteins to activate transcription of pair rule genes. These proteins divide the embryo into areas that are precursors of segmented body plan. Expression of these genes results in zebra stripe pattern along the anterior posterior axis, dividing the embryo into 15 subunits. Eight pair rule genes are known which include hairy, even skipped, runt etc. Mutations in these genes results in deletion of particular stripe. Pair rule proteins activate the segment polarity genes.
Segment polarity genes are responsible for organization of the segments. Mutations in segment polarity genes lead to deletion of part of the segment and replaced by a mirror image of the adjacent segment. Gene products of segment polarity genes play an important role in cell to cell signaling. They encode proteins that are involved in signal transduction pathways.
Homeotic genes are involved in determining the identity of individual segments. Homeotic gene products activate genes that encode segment specific characters. Mutations lead to specific body parts to appear in wrong segments. Homeotic genes create addresses for the cells of particular segments indicating the cells where they are within the region defined by segmentation genes.
When a Drosophila egg has been fertilized, its diploid nucleus immediately divides nine times without division of the cytoplasm creating a single multinucleating cell. After 8th division, nuclei get scattered in the cytoplasm followed by formation of 4 polar nuclei in 10th division. In the 13th division, nuclei divides and numerous nuclei are found in the periphery. This is called syncytial blastoderm. Each of these nuclei proved to have their own cytoplasmic environment rich in microtubules. Plasma membrane invaginates and each nuclei are surrounded by a membrane, which is called as cellular blastoderms. This has about 6000 cells. Polar cells give rise to germ cells and embryo undergoes further development. Three important genes are involved in the development of Drosophila; maternal effector genes/ egg polarity genes, segmentation genes, homeotic genes.
Egg polarity genes function in axis specification. These genes act by setting up a concentration gradient of morphogens in the developing embryo. A morphogen is a protein whose concentration gradient affects the developmental fate of the surrounding region. The egg polarity genes are transcribed into mRNA in the course of egg formation in the maternal parent and this maternal mRNA are incorporated in the cytoplasm of the egg. Proteins encoded by these mRNA play an important role in axis determination. These proteins are examples of maternal inheritance as the offspring will have similar phenotype.
Like in all other insects, fruit fly has a segmented body. When axis specification has taken place, segmentation genes control the differentiation of the embryo into individual segments. About 25 genes are included in segmentation genes. They are zygotic genes whose expression is controlled by bicoid and nanos protein gradients. Gap genes in segmentation genes are involved in defining large segments of embryo. Pair rule genes define regional sections of the embryo. Segment polarity genes are involved in organization of segments. Mutations in these genes lead to absence of certain segments.
Gap genes, which are regulated by maternal genes, are involved in dividing the embryo into broad regions each containing parasegment primodia. Hunchback proteins are expressed at the anterior end. Transcription of anterior gap genes are initiated by the different concentrations of hunchback and bicoid proteins. Higher concentration of hunchback proteins results in expression of giant proteins and prevents transcription of posterior gap genes in the anterior part whereas lower hunchback concentrations result in expression of kruppel proteins. Giant gene has two methods of activation; one for anterior expression band and one for posterior expression band. After this, gap genes become stabilized and maintained by interactions between different gap gene products. Protein products of gap genes interact with neighbouring gap gene proteins to activate transcription of pair rule genes. These proteins divide the embryo into areas that are precursors of segmented body plan. Expression of these genes results in zebra stripe pattern along the anterior posterior axis, dividing the embryo into 15 subunits. Eight pair rule genes are known which include hairy, even skipped, runt etc. Mutations in these genes results in deletion of particular stripe. Pair rule proteins activate the segment polarity genes.
Segment polarity genes are responsible for organization of the segments. Mutations in segment polarity genes lead to deletion of part of the segment and replaced by a mirror image of the adjacent segment. Gene products of segment polarity genes play an important role in cell to cell signaling. They encode proteins that are involved in signal transduction pathways.
Homeotic genes are involved in determining the identity of individual segments. Homeotic gene products activate genes that encode segment specific characters. Mutations lead to specific body parts to appear in wrong segments. Homeotic genes create addresses for the cells of particular segments indicating the cells where they are within the region defined by segmentation genes.
by BojanaL at 10-10-2012, 04:23 AM
18 comments
Various biotechnology careers include forensic DNA analyst, scientist, clinical research associate job, laboratory assistant, microbiologist, greenhouse and field technician, bioinformatics specialist, animal caretaker and many more.
Following is an interesting summary of options in Biotechnology as a career:
![[Image: jobtitles.gif]](http://faculty.ivytech.edu/~slee/images/jobtitles.gif)
Image courtesy: http://faculty.ivytech.edu/~slee/images/jobtitles.gif
A list of careers in biotech is long; here are few that sound really interesting:
Laboratory Assistant
US $4000-5000
In India, salaries may range between: INR 30,000-40,000 (or more, depending upon the experience)
Clinical Research Associate
Bioinformatics Specialist
Animal Caretaker
Production Engineer
A Production Engineer role can be obtained in any Biotechnology Product based company (like Cosmetics/FMCG, Pharmaceutical firms, Food industry etc). Role of a production engineer involves mapping process parameters to keep the line of production progressive (which is crucial for any large scale production company, especially pharmaceuticals).
Average Salary (per month) for a Production Engineer may range from:
US $6000-7000
In India, salaries may range between: INR 30,000-50,000 (depending upon experience, institute of study and company as well)
Qualiy Assurance (QA) Engineer
For becoming a quality assurance engineer in a biotechnology company, you need to have specialization/professional experience in Microbiology/Aseptic compliance. Role of a QA engineer is to ensure contamination free and standardized product formation. Controlling the the level of toxins, microbial contamination, proportions of various constituents is what comes under the role of a QA engineer.
Average Salary (per month) for a QA engineer may range from:
US $5000-6000
In India, salaries may range between: INR 25,000-30,000 (depending upon experience, institute of study and company as well)
Consultant
Companies like McKinsey, IBM, Evalueserve, Wipro, TCS, Deloitte etc hire biotechnology consultants for market research, knowledge process outsourcing, Audits, R&D etc.
Average Salary (per month) for a Consultant may range from:
US $6000-8000
In India, salaries may range between: INR 30,000-1,00,000 (depending upon experience, institute of study and company as well)
Number of people working in biotech industry in USA is exceeding 180.000. List of possible occupations is long and will expand as biotech is growing and moving in various directions with each new day. You just need to figure out what part of it you like the most.
A survey conducted by a private firm, to find out what are 10 happiest professions in America had some interesting findings. Conclusions were made after 200,000 people working in 70,000 different jobs were interviewed. A lot of things were taken under consideration: how much people appreciate their daily tasks, bosses, co-workers, salary, company culture and reputation…All examined subjects ranked how investigated factors correlate with their overall satisfaction. Salary wasn't most important factor for employee’s happiness. Type of a daily jobs, control over work done and relationship with colleagues were considered most important. Career that combines all necessary factors to make people enjoy time spent in their offices (laboratories) – is career in biotechnology!
Biotechnology is combining knowledge about life and living organisms with modern technology to create new systems, devices, materials, food…that could improve human life and help preserve environment. Most biotechnology products are associated with agriculture, food industry and medicine, and logically - careers in those fields are most popular.
Following is an interesting summary of options in Biotechnology as a career:
A list of careers in biotech is long; here are few that sound really interesting:
Laboratory Assistant
Scientific laboratory could perform different kind of research, but as a laboratory assistant your main duties will be sampling, measuring, collecting and analyzing investigated data… Maintenance of laboratory equipment such as centrifuges, titrators, pipetting machines…is also one of the tasks. Laboratory tests and strict methodology are very important especially when hazardous material is under investigation. Besides using typical lab equipment in work – computational analysis of given data is also important. High quality laboratory work is necessary for later research and development stages.
Average Salary (per month) for a laboratory assistant may range from:
US $1500-2500
In India, salaries may range between: INR 10,000-25000
Greenhouse and Field TechnicianAverage Salary (per month) for a laboratory assistant may range from:
US $1500-2500
In India, salaries may range between: INR 10,000-25000
Modern agricultural research is dealing with new, genetically modified plants. As a greenhouse and field technician, you’ll be in charge for planting seeds, pollinating plants, applying fertilizers and pesticides. Special attention to the problems that may arise (pest, disease…) is extremely important as those are genetically modified organisms. Basic knowledge of equipment used in everyday work as well as computer knowledge is also very important for this position.
Average Salary (per month) for a Green House and Field Technician may range from:
US $2500-3000
In India, salaries may range between: INR 15,000-30,000 (or more, depending upon the experience)
Forensic DNA AnalystAverage Salary (per month) for a Green House and Field Technician may range from:
US $2500-3000
In India, salaries may range between: INR 15,000-30,000 (or more, depending upon the experience)
This position is usually associated with crime laboratories where DNA analysis is performed to solve legal issues. Urine, saliva, blood, semen, hair…those are the samples that could be used for DNA analysis. After sample collection, DNA is extracted and analyzed using couple methods (PCR, electrophoresis). Final results are further compared with the already known DNA profiles. Methodology is strict: properly collected and stored evidence, documentation on technical laboratory details and well written final reports are essential for successful prosecution. Depending on the laboratory size, employees could be more or less specialized.
Average Salary (per month) for a Forensic DNA Analyst may range from:US $4000-5000
In India, salaries may range between: INR 30,000-40,000 (or more, depending upon the experience)
Clinical Research Associate
Clinical research associate (CRA) is monitoring clinical trials on a new drug. After preclinical studies (when tested on animals) are finished, drug is entering clinical trials where (depending on the study phase) smaller or larger group of people will be evaluated for possible adverse effects. CRA is included both in study design and in writing reports using given results. Close monitoring is especially important to make sure that protocol is not violated. Clinical data is collected, summarized and analyzed to help made final conclusion on a drug effect.
Average Salary (per month) for a Clinical Research Associate may range from:
US $4500-5000
In India, salaries may range between: INR 20,000-25,000 (or more, depending upon the experience and repute of the firm)
Average Salary (per month) for a Clinical Research Associate may range from:
US $4500-5000
In India, salaries may range between: INR 20,000-25,000 (or more, depending upon the experience and repute of the firm)
Bioinformatics Specialist
Bioinformatics is combining biology and computers. Data derived from various studies (DNA associated experiments, for example) is gathered in the computers. Software is in charge for data organization, manipulation and final analysis. Data mining is useful way to collect lot of publically available and jet relevant data that could be used in different experimental stages (for comparison or quick information extraction) or to help merge data from different sources. Programming skills are necessary for software and database manufacture and maintenance.
Average Salary (per month) for a Bioinformatics Specialist may range from:
US $5000-6000
In India, salaries may range between: INR 30,000-45,000 (or more, depending upon the experience and repute of the firm)
Average Salary (per month) for a Bioinformatics Specialist may range from:
US $5000-6000
In India, salaries may range between: INR 30,000-45,000 (or more, depending upon the experience and repute of the firm)
Animal Caretaker
Animal caretaker is nurturing animals used in biotech research. List of species used is long: all the way from mice and rats to cows and chimps. Water and food supplies, cage cleaning, animal health monitoring, relocation, milking, artificial insemination… a lot of duties need to be performed and not all tasks are representative. If you put aside that animals have specific odor (and different bodily fluids and excretions) keep in mind that watching animal suffer during experiments isn’t easy or nice thing to do.
Average Salary (per month) for an Animal Caretaker may range from:
US $1000-1200
In India, salaries may range between: INR 10,000-15,000
Average Salary (per month) for an Animal Caretaker may range from:
US $1000-1200
In India, salaries may range between: INR 10,000-15,000
Production Engineer
A Production Engineer role can be obtained in any Biotechnology Product based company (like Cosmetics/FMCG, Pharmaceutical firms, Food industry etc). Role of a production engineer involves mapping process parameters to keep the line of production progressive (which is crucial for any large scale production company, especially pharmaceuticals).
Average Salary (per month) for a Production Engineer may range from:
US $6000-7000
In India, salaries may range between: INR 30,000-50,000 (depending upon experience, institute of study and company as well)
Qualiy Assurance (QA) Engineer
For becoming a quality assurance engineer in a biotechnology company, you need to have specialization/professional experience in Microbiology/Aseptic compliance. Role of a QA engineer is to ensure contamination free and standardized product formation. Controlling the the level of toxins, microbial contamination, proportions of various constituents is what comes under the role of a QA engineer.
Average Salary (per month) for a QA engineer may range from:
US $5000-6000
In India, salaries may range between: INR 25,000-30,000 (depending upon experience, institute of study and company as well)
Consultant
Companies like McKinsey, IBM, Evalueserve, Wipro, TCS, Deloitte etc hire biotechnology consultants for market research, knowledge process outsourcing, Audits, R&D etc.
Average Salary (per month) for a Consultant may range from:
US $6000-8000
In India, salaries may range between: INR 30,000-1,00,000 (depending upon experience, institute of study and company as well)
Number of people working in biotech industry in USA is exceeding 180.000. List of possible occupations is long and will expand as biotech is growing and moving in various directions with each new day. You just need to figure out what part of it you like the most.
by nihila at 10-09-2012, 07:02 PM
1 comments
DNA nanotechnology is broadly divided into two branches - Structural and Dynamic DNA nanotechnology.
What is Nanotechnology?
Nanotechnology is the field of science and technology which is concerned with studies of substances and systems at the atomic and molecular level which is generally 100 nanometers or smaller. It is a rapidly developing field, the societal implications of which are already evident. And DNA nanotechnology is branch which aims to create novel, controllable nanostructures out of DNA by using its unique molecular recognition properties and to achieve molecular self-assembly through the manipulation of DNA. It is a technology in which molecular components spontaneously organize into stable structures; this form of structures is induced by the physical and chemical properties of the components selected by the designers. These components have strands of nucleic acids such as DNA, which are constructed in nanoscale as a nucleic acid double helix has a diameter of 2 nm and a helical repeat length of 3.5 nm. The most important property of nucleic acids is that the binding between two nucleic acid strands depends on simple base pairing rule which helps in assembly of nucleic acid structures easy to control through nucleic acid design. This technology is used in manufacturing of various nanomedicine which is used for various treatments of various diseases. It is helping scientists and researchers in creating synthetic vaccines that could one day help treat and prevent many potentially fatal diseases like cancer, AIDS, Hepatitis, influenza, etc.
DNA nanotechnology has two broadly divided branches-
One is Structural DNA nanotechnology (SDN) which focuses on synthesizing and characterizing nucleic acid complexes and materials that assemble into a static, equilibrium end state. It uses unusual DNA motifs to build target shapes and arrangements and these are generated by reciprocal exchange of DNA backbones, leading to branched systems with many strands and multiple helical domains. The motifs may be combined by sticky ended cohesion, involving hydrogen bonding or covalent interactions and other forms of cohesion involves edge-sharing or paranemic interactions of double helices. Some of these motifs are simple branched junctions, but other motifs represent more complex strand topologies, with greater structural integrity. Other than this double crossover (DX), triple crossover (TX), paranemic crossover (PX) and parallelogram motifs are of great use. The sequences of these unusual motifs are designed by an algorithm that attempts to minimize sequence symmetry. A core goal of DNA nanotechnology is the self-assembly of periodic arrays. Micron-sized 2-dimensional DNA arrays from DX, TX and parallelogram motifs can be constructed. Patterns can be changed by changing and modifying the components after assembly. DNA molecules have been used successfully in DNA-based computation as molecular representations of Wang tiles, who’s self-assembly can be programmed to perform a calculation.
The other is Dynamic DNA nanotechnology which focuses on creating nucleic acid systems with designed dynamic functionalities related to their overall structures, such as computation and mechanical motion. Some complexes have a combination of both the subfields such as nucleic acid nanomechanical devices. DNA complexes change their structure with change in some stimulus, making them one form of nanorobotics which is designed to have a dynamic reconfiguration after the initial assembly. Various devices like circuits, catalytic amplifiers, autonomous molecular motors and reconfigurable nanostructures have been designed to use DNA strand-displacement reactions where two strands with partial or full complementarity hybridized by displacing one or more pre-hybridized strands. This mechanism allows for the kinetic control of reaction pathways and buffer is required. Some systems can change with the change in control strands thus forming multiple devices which independently operate in buffer solution. Cascades of strand displacement reactions can be used for either computational or structural purposes and are energetically favorable through the formation of new base pairs, and the entropy gain from disassembly reactions. These cascades are conducted under isothermal conditions for the assembly or computational process. They can also support catalytic functionality of the initiator species, where less than one equivalent of the initiator can cause the reaction to go to completion. These strand displacement complexes are used to form molecular logic gates capable of complex computation and these molecular computers use the concentrations of specific chemical species as signals. In nucleic acid strand displacement circuits the signal is the presence of nucleic acid strands that are released or consumed by binding and unbinding events to other strands in displacement complexes.
What is Nanotechnology?
Nanotechnology is the field of science and technology which is concerned with studies of substances and systems at the atomic and molecular level which is generally 100 nanometers or smaller. It is a rapidly developing field, the societal implications of which are already evident. And DNA nanotechnology is branch which aims to create novel, controllable nanostructures out of DNA by using its unique molecular recognition properties and to achieve molecular self-assembly through the manipulation of DNA. It is a technology in which molecular components spontaneously organize into stable structures; this form of structures is induced by the physical and chemical properties of the components selected by the designers. These components have strands of nucleic acids such as DNA, which are constructed in nanoscale as a nucleic acid double helix has a diameter of 2 nm and a helical repeat length of 3.5 nm. The most important property of nucleic acids is that the binding between two nucleic acid strands depends on simple base pairing rule which helps in assembly of nucleic acid structures easy to control through nucleic acid design. This technology is used in manufacturing of various nanomedicine which is used for various treatments of various diseases. It is helping scientists and researchers in creating synthetic vaccines that could one day help treat and prevent many potentially fatal diseases like cancer, AIDS, Hepatitis, influenza, etc.
DNA nanotechnology has two broadly divided branches-
One is Structural DNA nanotechnology (SDN) which focuses on synthesizing and characterizing nucleic acid complexes and materials that assemble into a static, equilibrium end state. It uses unusual DNA motifs to build target shapes and arrangements and these are generated by reciprocal exchange of DNA backbones, leading to branched systems with many strands and multiple helical domains. The motifs may be combined by sticky ended cohesion, involving hydrogen bonding or covalent interactions and other forms of cohesion involves edge-sharing or paranemic interactions of double helices. Some of these motifs are simple branched junctions, but other motifs represent more complex strand topologies, with greater structural integrity. Other than this double crossover (DX), triple crossover (TX), paranemic crossover (PX) and parallelogram motifs are of great use. The sequences of these unusual motifs are designed by an algorithm that attempts to minimize sequence symmetry. A core goal of DNA nanotechnology is the self-assembly of periodic arrays. Micron-sized 2-dimensional DNA arrays from DX, TX and parallelogram motifs can be constructed. Patterns can be changed by changing and modifying the components after assembly. DNA molecules have been used successfully in DNA-based computation as molecular representations of Wang tiles, who’s self-assembly can be programmed to perform a calculation.
The other is Dynamic DNA nanotechnology which focuses on creating nucleic acid systems with designed dynamic functionalities related to their overall structures, such as computation and mechanical motion. Some complexes have a combination of both the subfields such as nucleic acid nanomechanical devices. DNA complexes change their structure with change in some stimulus, making them one form of nanorobotics which is designed to have a dynamic reconfiguration after the initial assembly. Various devices like circuits, catalytic amplifiers, autonomous molecular motors and reconfigurable nanostructures have been designed to use DNA strand-displacement reactions where two strands with partial or full complementarity hybridized by displacing one or more pre-hybridized strands. This mechanism allows for the kinetic control of reaction pathways and buffer is required. Some systems can change with the change in control strands thus forming multiple devices which independently operate in buffer solution. Cascades of strand displacement reactions can be used for either computational or structural purposes and are energetically favorable through the formation of new base pairs, and the entropy gain from disassembly reactions. These cascades are conducted under isothermal conditions for the assembly or computational process. They can also support catalytic functionality of the initiator species, where less than one equivalent of the initiator can cause the reaction to go to completion. These strand displacement complexes are used to form molecular logic gates capable of complex computation and these molecular computers use the concentrations of specific chemical species as signals. In nucleic acid strand displacement circuits the signal is the presence of nucleic acid strands that are released or consumed by binding and unbinding events to other strands in displacement complexes.
by Kamat2010 at 10-09-2012, 06:08 PM
2 comments
Type I Diabetes is an epidemic disease of the modern times, which is non-infectious. In this disease, the beta cells in the pancreas are diseased or lost thereby affecting the insulin production, leading to abnormal blood sugar levels in the blood. The frequent dose of insulin injections can help the patients to maintain the blood sugar level in blood, but it does not provide any permanent solution. The curative treatment for the disease is the replacement of the lost beta cells with functional beta cells by pancreas or islet cell transplant. However, the shortage of donors has initiated for the study of alternative treatments for the same. The stem cell therapy has proved to be a very potent solution for the diabetes treatment compared to other treatments as the disease is characterized by the loss of a single type of cells in the disease and hence could be treated successfully if the cells could be replaced or replenished within the body.
The use of stem cells in the therapy involves at first the thorough study of the signalling mechanisms in the formation of the pancreatic beta cells from the embryonic stem cells, mainly the Notch signalling mechanism, which stimulates the creation of the beta cells in the developing foetus after inhibiting the same at first. With the study of the various signalling processes within the body, the scientists have succeeded in the formation of functional beta cells in pancreas, which secrete insulin, from the embryonic stem cells. Stem cells could also provide an alternate treatment by helping in the pancreatic recovery, thereby helping in the replenishment of the beta cells secreting insulin. It has been proved by the successful study in mouse models that when the gene for the vascular endothelial growth factor (VEGF) is expressed in the modified bone marrow stem cells, the pancreatic recovery is sustained with the formation of new beta cells, thereby helping in insulin production. The modified stem cells help in the formation of new blood vessels and activate the genes responsible for insulin production.
Type I diabetes results due to autoimmune disorder, in which the immune cells affect and destroy the pancreatic beta cells, thereby affecting insulin production. Research studies have shown that the aggression of the immune system can be treated with the combination of stem cell therapy and immune suppression drugs. In this treatment, the abnormal immune system cells are suppressed and destroyed by the drugs and are then, replaced by the immature stem cells, which differentiates into normal immune system cells, thereby preventing the destruction of beta cells and help cure Type I diabetes. Cord blood stem cells have also been used for the treatment of the autoimmune disorder of Diabetes, which follows the ‘Stem cell education therapy’. In this procedure, the cord blood stem cells of the healthy donor secreted the Autoimmune regulator (AIRE) that effected changes in the lymphocytes of the patient when they are co-incubated, thereby preventing the autoimmune attack on the pancreatic beta cells and helping in their recovery.
Research studies have shown that neural stem cells from the hippocampus and olfactory bulb were successful in differentiating into pancreatic beta cells when transplanted into the pancreas of diabetic rats and could secrete insulin, thereby helping in the diabetes treatment. This could provide a solution for the non-availability of donors of stem cells or pancreas as the patient himself could be the donor of neural stem cells essential for the treatment. However, in-depth research is essential for translating the studies on rodents to that on human patients.
In the treatment of diabetes, the stem cell therapy is indicated in almost all the stages of the diseases. However, it is most effective when applied in the initial onset of the disease; in case of renal failure in the diabetes patients; immunodeficiency disorders; development of Diabetes mellitus Type II, etc. Although, the stem cell therapy may prove to give beneficial results on the sufferers, but the scientists need to study thoroughly the possible side effects on the other mechanisms within the body, which is possible only by carrying out further scientific investigation on the subject. The pathways of the differentiation processes must be elucidated properly for the translational studies on higher animals as the research has been carried out mainly on rodent models. A revolution in the world of therapeutics can be expected in future, keeping the vast scope of stem cell research in mind.
The use of stem cells in the therapy involves at first the thorough study of the signalling mechanisms in the formation of the pancreatic beta cells from the embryonic stem cells, mainly the Notch signalling mechanism, which stimulates the creation of the beta cells in the developing foetus after inhibiting the same at first. With the study of the various signalling processes within the body, the scientists have succeeded in the formation of functional beta cells in pancreas, which secrete insulin, from the embryonic stem cells. Stem cells could also provide an alternate treatment by helping in the pancreatic recovery, thereby helping in the replenishment of the beta cells secreting insulin. It has been proved by the successful study in mouse models that when the gene for the vascular endothelial growth factor (VEGF) is expressed in the modified bone marrow stem cells, the pancreatic recovery is sustained with the formation of new beta cells, thereby helping in insulin production. The modified stem cells help in the formation of new blood vessels and activate the genes responsible for insulin production.
Type I diabetes results due to autoimmune disorder, in which the immune cells affect and destroy the pancreatic beta cells, thereby affecting insulin production. Research studies have shown that the aggression of the immune system can be treated with the combination of stem cell therapy and immune suppression drugs. In this treatment, the abnormal immune system cells are suppressed and destroyed by the drugs and are then, replaced by the immature stem cells, which differentiates into normal immune system cells, thereby preventing the destruction of beta cells and help cure Type I diabetes. Cord blood stem cells have also been used for the treatment of the autoimmune disorder of Diabetes, which follows the ‘Stem cell education therapy’. In this procedure, the cord blood stem cells of the healthy donor secreted the Autoimmune regulator (AIRE) that effected changes in the lymphocytes of the patient when they are co-incubated, thereby preventing the autoimmune attack on the pancreatic beta cells and helping in their recovery.
Research studies have shown that neural stem cells from the hippocampus and olfactory bulb were successful in differentiating into pancreatic beta cells when transplanted into the pancreas of diabetic rats and could secrete insulin, thereby helping in the diabetes treatment. This could provide a solution for the non-availability of donors of stem cells or pancreas as the patient himself could be the donor of neural stem cells essential for the treatment. However, in-depth research is essential for translating the studies on rodents to that on human patients.
In the treatment of diabetes, the stem cell therapy is indicated in almost all the stages of the diseases. However, it is most effective when applied in the initial onset of the disease; in case of renal failure in the diabetes patients; immunodeficiency disorders; development of Diabetes mellitus Type II, etc. Although, the stem cell therapy may prove to give beneficial results on the sufferers, but the scientists need to study thoroughly the possible side effects on the other mechanisms within the body, which is possible only by carrying out further scientific investigation on the subject. The pathways of the differentiation processes must be elucidated properly for the translational studies on higher animals as the research has been carried out mainly on rodent models. A revolution in the world of therapeutics can be expected in future, keeping the vast scope of stem cell research in mind.
by priyasaravanan_1406 at 10-08-2012, 11:33 PM
3 comments
Our immune system acts as the protective shield of our body against various infections by bacteria and virus causing various diseases. White blood cells, the army of immune system is composed of neutrophils, eosinophil, basophil, lymphocyte and monocyte each carrying out its unique function in fighting against the foreigner entering the body. The B cells of the lymphocytes are the intelligent soldiers which recognize the type of foreign object (antigen) entering the body and releases a weapon called antibody to track the foreigner and destroy them. The two novel traits of an antibody are its specificity to the antigen and once induced its assurance to the body to provide continual resistance to the particular type of disease acquired. Baffled by these two unique features of an antibody, scientists decided to use them for the welfare of the human kind and developed techniques to produce antibodies in vitro. The result is the production of ‘Monoclonal Antibody’.
Monoclonal antibody is the term used for the antibody produced in vitro by multiplying a single hybrid cell, obtained by cloning selected cells from a single source. Monoclonal antibodies are known for its purity and specificity. The conventional method of monoclonal antibody production was done by injecting the test animal with a particular type of antigen. After few days of the dose of the antigen, blood is drawn from the test animal and the antibodies were extracted from the serum of the blood. This method was failure both qualitatively and quantitatively. The antibodies obtained were found to be impure (mixed variants) and the amount obtained was also significantly less. Hence adoption of cloning technique was identified as the optional method to produce antibodies in vitro.
In this method, scientists selected tumor cells for its ability to multiply intensively and the antibody producing mammalian cells and fused these two under in vitro conditions. On the onset of the production, the test animal usually a mice is injected with an antigen to stimulate the antibody production. The antibody producing cells are identified and extracted from the spleen of the mice and it is fused with the myeloma cells which were extracted from the mice earlier and cultured in vitro. The resulting hybrid cell or hybridoma is observed for the presence of the desired antibody and once satisfied, the hybrids are subjected to grow in culture to produce splendid quantity of monoclonal antibodies. Again, the extraction and purification of the monoclonal antibody from the hybridoma is done by sequence of processes like centrifugation, filtration, ultra filtration or dialysis and ion exchange chromatography. Later the ion exchange chromatography was replaced by size exclusion chromatography which was found to be more effective in purifying. Also a procedure called affinity purification was employed to obtain the maximum purity. After undergoing the steps of purification, the final product, the monoclonal antibody is checked for the level of purity by using either chromatogram or gel electrophoresis or capillary electrophoresis.
The first test animal used for the production of monoclonal antibody is mice and a consequence reaction like allergy was observed in humans when supplemented with the monoclonal antibodies produced from mouse cell. Also, humans responded only to the initial dose and developed resistance to further doses. This posed as a bigger problem in obtaining the benefits of the monoclonal antibody and as a result evolved the chimeric antibody. The chimeric antibody is developed by inserting some human amino acid sequence into the animal developed monoclonal antibody.
The novel idea of developing fully human monoclonal antibody is a major breakthrough in the production of monoclonal antibody. In this method, blood sample is collected from an individual (donor) recovered from a particular type of infection and the antibody specific cells are extracted and immortalized. These cells are then subjected to micro well assay technique and the antigen specific antibodies are identified by fluorescence method and isolated. These cells are expanded and characterized before passing to other cell types for large scale production. The difficulty in identifying a donor is eluded by extracting cell from a healthy person and activating the cell for specific antibody production in vitro. The advancement in genetic engineering technology serves the human monoclonal antibody production by using transgenic mice.
The wide therapeutic application of monoclonal antibodies states the significance of the production of the monoclonal antibody.
Monoclonal antibody is the term used for the antibody produced in vitro by multiplying a single hybrid cell, obtained by cloning selected cells from a single source. Monoclonal antibodies are known for its purity and specificity. The conventional method of monoclonal antibody production was done by injecting the test animal with a particular type of antigen. After few days of the dose of the antigen, blood is drawn from the test animal and the antibodies were extracted from the serum of the blood. This method was failure both qualitatively and quantitatively. The antibodies obtained were found to be impure (mixed variants) and the amount obtained was also significantly less. Hence adoption of cloning technique was identified as the optional method to produce antibodies in vitro.
In this method, scientists selected tumor cells for its ability to multiply intensively and the antibody producing mammalian cells and fused these two under in vitro conditions. On the onset of the production, the test animal usually a mice is injected with an antigen to stimulate the antibody production. The antibody producing cells are identified and extracted from the spleen of the mice and it is fused with the myeloma cells which were extracted from the mice earlier and cultured in vitro. The resulting hybrid cell or hybridoma is observed for the presence of the desired antibody and once satisfied, the hybrids are subjected to grow in culture to produce splendid quantity of monoclonal antibodies. Again, the extraction and purification of the monoclonal antibody from the hybridoma is done by sequence of processes like centrifugation, filtration, ultra filtration or dialysis and ion exchange chromatography. Later the ion exchange chromatography was replaced by size exclusion chromatography which was found to be more effective in purifying. Also a procedure called affinity purification was employed to obtain the maximum purity. After undergoing the steps of purification, the final product, the monoclonal antibody is checked for the level of purity by using either chromatogram or gel electrophoresis or capillary electrophoresis.
The first test animal used for the production of monoclonal antibody is mice and a consequence reaction like allergy was observed in humans when supplemented with the monoclonal antibodies produced from mouse cell. Also, humans responded only to the initial dose and developed resistance to further doses. This posed as a bigger problem in obtaining the benefits of the monoclonal antibody and as a result evolved the chimeric antibody. The chimeric antibody is developed by inserting some human amino acid sequence into the animal developed monoclonal antibody.
The novel idea of developing fully human monoclonal antibody is a major breakthrough in the production of monoclonal antibody. In this method, blood sample is collected from an individual (donor) recovered from a particular type of infection and the antibody specific cells are extracted and immortalized. These cells are then subjected to micro well assay technique and the antigen specific antibodies are identified by fluorescence method and isolated. These cells are expanded and characterized before passing to other cell types for large scale production. The difficulty in identifying a donor is eluded by extracting cell from a healthy person and activating the cell for specific antibody production in vitro. The advancement in genetic engineering technology serves the human monoclonal antibody production by using transgenic mice.
The wide therapeutic application of monoclonal antibodies states the significance of the production of the monoclonal antibody.
by Mandokir at 10-08-2012, 11:26 PM
4 comments
Hello forum members,
We are looking to bind single cell genomic DNA to microbeads and perform a whole genome amplification on the beads. We want to perform a non PCR ampificiation.
The idea is to bind the DNA to the microbeads using the streptadivin - biotin system. We need the DNA bound to microbeads while leaving the DNA available for amplification, thus we want to bind the fosfate backbone with DNA binding proteins.
I have a few questions:
1) Do you think it is feasable to perform whole genome amplfication on microbeads?
2) Can annyone suggest a DNA binding protein that we could biotinylate to produce a probe that leaves the bound DNA available to amplification?
3) Do you have a different suggestion as to how we could bind DNA to microbeads, and subsequently perform a DNA amplification?
Greetings
We are looking to bind single cell genomic DNA to microbeads and perform a whole genome amplification on the beads. We want to perform a non PCR ampificiation.
The idea is to bind the DNA to the microbeads using the streptadivin - biotin system. We need the DNA bound to microbeads while leaving the DNA available for amplification, thus we want to bind the fosfate backbone with DNA binding proteins.
I have a few questions:
1) Do you think it is feasable to perform whole genome amplfication on microbeads?
2) Can annyone suggest a DNA binding protein that we could biotinylate to produce a probe that leaves the bound DNA available to amplification?
3) Do you have a different suggestion as to how we could bind DNA to microbeads, and subsequently perform a DNA amplification?
Greetings